Re: Do you know how to make an electric kit?
There was a DIY project in "Electronic Musician" magazine about 20 years ago involving getting these old skool piezo buzzers from Radio Shack and dismantling them and attaching it to the underside of a remo practice pad head and then soldering the leads to a 1/4" jack so you could plug it into a module. I think the results were favourable but you ended up having to build extra pick-ups as they were a bit fragile.
When I had a Roland Octapad Pad-80 years ago I opened it up and on the underneath of every pad, was the familiar piezo tranducer! But it was much more robust because the actual pads were a plastic on top of a hard layer of rubber, which was glued to a metal sheet, and then the piezo was attached to that with glue.
However, depending on your budget, I too think you'd be better off finding a used Roland V-Drum kit. I've seen older TD-10 kits selling for as little as $1100 on eBay and when I owned one, I bought it used for about that much from a friend. So deals can be had and although it could be a bit expensive to get a pad sensor fixed by Roland, I think it's cheaper in the long run to have something that you can play without having to worry about too much maintenance.