Hey i'd recommend a vivarium which is preferably at least 15 gallon for one leopard gecko, bigger for two
I've recently had to have a look around for a good vivarium and would recommend a wooden style one as it retains the heat much better.
I'd advise not to go for a pets at home type starter kit as it doesn't include essentials and the one i looked at for leos was a glass one.
Best places are any local specialist reptile stores you can find, i personally had to travel an hour to Birmingham but it was worth it ! Also reputable online suppliers could have good vivs.