If you're looking for an item in the middle of the price range, why not consider this P.A.R.O.S.H. Tank. While the price is very reasonable, this piece is an easy wardrobe update. It's also worth taking a look at this 3.1 Phillip Lim Tank. This product is ultra popular and, just as importantly, not too pricey.
If you're looking at it like an investment piece, then you absolutely must check out this Marni Tank. This piece seems pricey, but it's well worth it. Why not take a look at this Courreges Tank too? Expensive, but worth every penny.