Where can I get a low back shapewear?

[outwiththeoldforgood]

My wedding dress is very low back and I need a shapewear that will help me conceal my tummy without being visible at the back if that makes sense? I'm only going to wear it once so anything cheap would be nice. I've searched the internet but I can't find anything and the ones I can see on there are about £50 which I think is too much