HMV is currently doing a clearance sale, and amongst the items on sale is Samurai Shodown Sen for the 360 at the low price of £4. Although not the greatest game released by SNKP, at £4 it's well worth a try. (And if you don't like it the trade in exchange value at CEX is for £4 too.)
Also on sale is KOFXII for 360 (£7) and PS3 (£9), not sure how cheap this game goes for these days but a quick look around other online retailers, and this seems to be the cheapest price that i can find.
Also this Saturday Gunsmith (Orochinagi) will be hosting a KOF94 and 02UM tournament at Gamerbase Trocadero. Check out Orochinagi's website for more details of how to sign up and prize details.