Presently you should expect to pay about $12M for almost any F1 and more than that for certain examples. There might be a few GTR "bargains" still around that could be had under $10M, perhaps, but the trend of them being less expensive than the road cars has been reversing rather rapidly.
The 1:21.2 time you have quoted relates to what circuit? If Tsukuba, it was in the hands of Naoki Hattori and he's certainly capable.
>8^)
ER