I wrote this a few months ago:
http://www.amibay.com/showthread.php?t=16681Sums up pretty much all you need to know about A1200 accelerators.
If you're looking in the £50-£80 region, you're probably looking at anywhere between a plain FastRAM card and a budget '030 accelerator. Best bang-for-buck is probably the ACA1230/28 at £85-ish.
Don't bother with PCMCIA FastRAM on an A1200, it's only 16-bit and will actually make your A1200 run
slower. They're great for basic A600s, but a trapdoor card makes far more sense for an A1200.