^ This along with all the little air pillows. I've been using them at will lately just to reduce the amount of space taken up by them.
I've been thinking about this person who is selling their collection .. maybe their end game isn't quitting but rather trying to take their profits in one lump sum and move on? If they manage to sell anywhere close to their 28k asking price, they must have made some cash overall.
If you're moving a lot of volume, taking a smaller return for such little work (you didn't have to source any of the sets) might be worth it. If you're a long-haul investor, you probably want a little better deal for the risk/storage factor.
I do feel the need to point out that using the BP value as the overall value is a huge red flag to me. Many of those sales to US customers include the cost of shipping in the overall value (when a listing has free shipping, obviously that can't be filtered out). There are a ton of big sets too, shipping isn't that cheap that you can ignore it... So from the 33.5k estimate, take about 6% off the top for shipping and material costs. Now if you sell on eBay, take roughly another 12% off (9% + 3% .. assuming seller probably qualifies for a small discount). That brings us to: 33,500 - 4020 (fees) - 2010 (shipping) = 27,470.
Looks to me like this seller would profit handsomely from a 28k given some sets are retired and many (if not all) were likely sourced below MSRP. Advertising the overall value at 33.5k with a discount to 28k is just marketing.... a number designed to get you to negotiate less.
If you wanted to make 20% today, 22k is the max price. For 10% its 24.7k. If you already have the storage facility + work area, getting 10% off is decent. Plenty of those sets still have room to grow. If I was interested, I'd start at 21 and try to meet around 23. Alas, I'd be in the most trouble ever if I ever made a purchase like that without consulting the other income earning adult in the house.