Ah a kindred spirit! I don't do hobbyshop after market stuff either... There's plenty of stuff around the house...
In 1/48th, 1/35th and 1/32nd, I use different stuff, with good results all around.
1. Masking Tape
2. Fabric Surgical tape.
The tapes are good because of the textures in them, especially the surgical tape. You might have to look at several brands to get the texture you want.
3. Aluminum Foil- Holds any shape you want it to, heavy-duty BBQ type is best.
4. Flattened solder. My personal favorite... Same reason as foil, but more rugged and will hold up to trimming better. I flatten solder with a tack hammer and small jeweler's anvil, but I also use the flat of a pair of pliers to squeeze it flat.
The tapes take paint easier, and won't chip if bend after painting, but solder/foil can be draped in much more subtle manners, looking more like real strapping.