Given you don't want a snake or a cricket eater my first instinct was Blue Tongue Skink.
BTSs are not so common so could cost a bit to buy, and you'll need a 4' viv to hold him, though you can build your own quite cheap. You'll also need heating and possibly UV. It will be just inside your limit I think. But they are wonderful, laid back, intelligent pets who will interact with you like no other lizard. Take a look online for a caresheet and a few picsture.
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