Mate, you have a way with words. "I want a something like one of those DIY stoves tramps can make from of old cans...but cheaper."
I made my top loaders from sugar tins and drainers found in Pound Shops and catering size bean tins from the canteen at work. I also sent all posh and made a grate from weaving ni-chrome wire from a defunct electric fan heater. With materials that cheap, just have at it with a combination of imagination and what you can glean from photos and youtube. I found that how well the designs work is fairly execution dependent, meaning that unless you are able to follow a very exact recipe, your results may vary and your design may need adjusting to suit what you are working with. Different diameters of drainer, tin, holes, wood, pot and what tools you have. Cutting up drawn stainless tins without a Dremel or similar isn't so easy.
If you are looking to buy one...meh, I like my original Bush Buddy, but for 90% of what I do I think burning wood is over rated. If I am playing at camping, it is fun. If I am camping because I am travelling far from home and in strange lands, cooking on twigs can be a tremendous pain in the posterior.....sorry, started off on a tangent. Best of luck! stove making IS fun, even if I no longer find it practical.