You may want to at least consider a tub while it's young and needing a very small enclosure...think of it like buying a crib for a baby human if that helps.

Also there are a couple of choices sort of mid-point between tubs and tanks. There's some lovely enclosures at www.reptilebasics.com and there's also the Iris brand of plastic tubs. Iris isn't as easy to find as Rubbermaid and Sterlite. I find mine at my local OfficeMax. They are plastic but are such high quality that they are absolutely glass clear and have a smooth interior, something you come to appreciate after chipping hard as concrete urates out of a ridge in a tub. Iris is a big more expensive generally than Rubbermaid or Sterlite but well worth it in my opinion.