I once paid over $300 for a package of vintage Pampers from the 1980s. Now the prices are well over $500, and sometimes they reach the thousands. That's too rich for my blood, so I'm out of the vintage diaper trade for now.
The most I've spent is $50 for my pirate onesie, I've also spent between $25 - $50 on things like the Little Keeper Sleeper and other onesies and footed PJ's. My diaper purchases aren't as big as ultrapampers, I mostly stick to ATN's and Abenas. I'm considering spending a bit on the Waddler Overnights because they are on clearance for 25% off right now.