Before discussing this chapter in depth, Keil and Delitzsch note that Lev 26:46 denotes the end of the Levitical law. This chapter is therefore a separate appendix, which is more bureaucratic than anything else. In spite of its separation from the Levitical laws, it is still obviously part of the overall Mosaic law.
In order to understand this chapter, we have to first understand a few of the key concepts being discussed: what is the purpose of these valuations, what does it mean to "consecrate" (Hebrew "qadash", closely related to "qodesh" meaning sacred or holy) your house or a field or an animal, how does this relate to a vow (v. 2), and how does that relate to "redeeming" (Hebrew "ga'al") things. These concepts are not particularly explained, so we have to read into the context of the chapter what is going on. In broad terms, we see two general patterns. The first pattern is in verses 2-8, which establishes the valuation of persons who make a "vow" (Hebrew, "neder") to the LORD. The second pattern is from v. 9-29, discussing the consecration of animals, houses and land, each of which contains its own special cases and valuation principles.
What is a vow? From a simple linguistic perspective, a vow is a promise to God to do something over some duration of time. It is extremely general. Consider, for instance, Jacob's "vow" (the same word, "neder") in Gen 28:20, where he promised to build a "house of God" and give God a tithe if the LORD protects him on his journey. This aptly demonstrates the variable nature of a "neder". Probably the most famous vow in the OT is the Nazirite vow, which we will encounter in Numbers 6.
Many commentators think of the vow as a "promise to give [something] to God", i.e. that the vow of v. 2 is someone promising to give a person, whether him or herself or a dependent or slave to God. Generally, they also read this is devoting things to the tabernacle or the center of worship which is represented by the priest. While this position is defensible, I am not convinced because the very first example, Jacob, is not vowing a person but rather he is vowing actions, that he would return and construct a temple to God if he were blessed in a certain fashion.
In the case of a vow, the person is assigned a fixed valuation depending on age and gender and this valuation seems to roughly correspond with economic value (primarily valuing middle-aged men, who would have been the most economically productive). There is a hardship test as well, to reduce the cost for those who cannot afford the full price. This surprises me considering that vows are almost certainly voluntary and this chapter is not discussing any mandatory portion of the Mosaic law. The obvious question is, what is the valuation and what does it mean? We are never told this in the bible, but given my analysis of vows in the prior paragraph, I think it's possible that the valuation is a redemption price if a person decides that they cannot (or will not) fulfill a given vow. Other commentators think that every person must be redeemed because unlike the cases of animals, houses and land, a person cannot be sold off or sacrificed. There is no way for the priest to dispose of people the way he disposes of other consecrated things, so redemption is the only realistic alternative.
So, I've stated my opinion, but since everyone is trying to interpret the context, the true answer could be any of the above. What is clear is that people in Israel could vow an offering of nearly anything they possess (including people) and rather than establish the rules for vows, this chapter is establishing a pricing schedule for what happens if someone wishes to later redeem a thing they have vowed. I remember the thing that confused me the most about this chapter is, "why would someone vow something and then redeem it by paying money?" It seemed silly to me, but I guess that just shows how little we know about Israelite culture, that of the entire process of vowing possessions and redeeming them, the only thing that was preserved was the pricing guidelines for redemption.
This chapter continues with more special cases for clean animals versus unclean animals (which I won't discuss) and the consecration of land. The main deal with consecrated land is that vowing a piece of land to the LORD also follows the Jubilee pricing rules that we saw back in Lev 25: the land is not given away, only certain years of crops from that land. The redemption price must therefore correspond both to the size of the property (based on how much seed is used to plant it) and how long until the next Jubilee (how many crops may be planted before the land returns to its owner). The one peculiarity to all this is that if a man vows a property and then sells it without redeeming it, then he does not receive the land back at the Jubilee. I don't entirely understand how a man can consecrate a field and still possess the rights to sell it. This seems to suggest that the man can vow to give a property and not do so for some time, and by extension this is probably true for consecrated animals, houses and people as well. But since the valuation of land reduces from year to year (when moving towards the Jubilee), then that means either the redemption price decreases from year to year, or that the redemption price is fixed when a vow is made and the redemption price subsequently increases to greater than the (now lowered) land value as the number of crops until the Jubilee goes down.
I do believe that there is an implied time delay between making a vow and fulfilling the vow (by giving that thing to the priest), but without seeing the detailed rules, it is difficult to interpret precisely how that time delay works. The examples we see in the OT tend to be very flexible and do not appear to have any particular rules or guidelines (Jacob's vow, Hannah's offering of Samuel, the Nazirite vow), and yet this chapter is presuming an apparently fixed set of rules regarding how to redeem a vowed possession.
That's about all I can say on this topic, so I will move on to one last subject, which is "the tithe of the land" (v. 30). As before, this chapter is not instituting a tithe, but simply discussing the price structure for if anyone wishes to redeem part of their tithe. This leaves us wondering what tithe is under discussion, since the only tithes mentioned before were a one-off offering by Abraham (Gen 14:20) and a promised offering by Jacob (Gen 28). There is no systematic tithe in the Pentateuch yet, so the most probable answer is that this chapter is referring to the tithe in Numbers 18, which I will discuss at length when I comment upon that chapter. For the purpose of analyzing this chapter, it doesn't matter too much which tithe is being referred to. What seems clear from the context is that this chapter is not establishing a tithe in itself because it is presuming that the reader is already aware of the required tithe. Also, it would be out of context to establish a tithe here when the theme is clearly "valuations for the redemption of offered things".
I promise to write a lot more about tithes when we read about them in Numbers and Deuteronomy, and with that I conclude my discussion of Leviticus and we can move on to the book of Numbers.