"Last year, I bought a PCGS MS70 First Strike $5 Gold Buffalo and a PCGS PR69 FS $5 Gold Buffalo. I wanted to get the MS69 and PR70 of the same type, but I waited too long and now I can't find any up for sale on eBay or any other bullion/coin site. Anyone know where I can find one or both of them?"
If I understand you correctly, you are looking to buy a certain type of gold bullion coin in a certain type of TPG labeled coin holder.
I think I understand you to mean that you want the TPG to be PCGS, you want the gold bullion to be issued by the US Mint, you want the design to be a copy of the Buffalo nickel, you want the bullion to be dated and denominated "2008 $5", you want one to be labeled as being graded "MS-69" and the second "PR-70", and you want both coin holders to be labeled with a "First Strike" sticker.
That doesnt sound like such a hard item to find.
That type of thing is available on eBay.
