A regular sewing machine will do light leather (3-4) but not with real heavy thread, maybe up to a 60 range, but that will work for a lot of things. You need to get a leather needle but most common sewing shops have those for standard machines. For leather you really should be able to sew with a 92 thread.
I bought a Tippman and use it for heavy work but for most light stuff and flatgoods I use an Artisan with mostly 138 thread. My original commercial power machine was an old Singer made in 1941 with no reverse, I asked at every boot and shoe repair shop around until I got a line on one and table, motor, and all bought it for $200. It had a roller foot which I finally changed out but I used it a lot. A friend now has it and does lots of motorcycle stuff with it. If you have a commercial sewing supply go there and see what they have? JL