You could make one by tipping a large wardrobe on Tue TS side and knocking some of the wood panels in the doors out and replacing them with the sort of wire on bird cages bit make sure its fascend on the outside and the gaps are at most 1.5cm wide and use horizontal wire. Also a tarpaulin on the floor stapled around 1 inch high would stop it rotting and use newspaper on top of the tarp so it is easier to clean. If not just look on eBay or preloved

Can you be more specific please?

I plan on getting some budgies, probably three. I really want to give them an indoor aviary so they have enough space and I can keep them healthy and happy. The problem is I can't find one that's suitable. Does anyone know any sites that sell good budgie aviaries? I live in the UK so no US sites.