TW currently have a budget rebuildable, it's polycarbonate with silica setup, but for about £11 on yoyo, it's not a bad buy if you are looking for a first time rebuildable and don't want to shell out for a more expensive item.
I saw DID clones for just under a tenner, but think it was the US, Discountvapers. Don't know anything for the quality, so it's a "take your chance". There are others, like in the China shops, same sort of thing, but again, I've not tried them. Just ordered 2 Oddy clones in China, for 17,50€ each, post included, but they're flying China Airmail, so I'm doing the big wait