Ah, Narf, you and I have similar tastes. I'm missing 5 issues for the complete Silver Age Doom Patrol run, I think. I've got both MGA 80 and Doom Patrol 121; both bought years ago. I think I paid $30 for the beat up MGA 80, and that's probably the only issue I ever paid over $20 for. One of the great Silver Age DC books.
Adventure #247 remains the most I've ever paid for a comic; even a beat up one. But it was worth it to me to be able to say I have a complete run of the Legion. And, amazingly, while there are at least 10 reprints of that story out there, there has NEVER been an unedited one! The first reprint dropped a page, the next two were digest size, and all later ones (other than in black & white) edited the coloring.