wide-angle and pancake Lenses

Hi;

I'm new here; I've recently substancially upgraded my digital photography kit, moving from a 9-year old samsung L73 to a new Panasonic GX7, with the 14-42mm zoom (I'd looked at DSLRs, but the general concept always feels like a bit of a bodge, so I went mirrorless). In the intervening time, I've been getting into photography via the 35mm route; I'd inherited an old Praktica BC1, along with a few lenses; a 28mm, a 20mm, and a zoom; I picked up a 50mm lens too. Since picking up the new panasonic, I've also picked up a 42mm adapter, and a couple of 42mm lenses; A 50mm F1.8 helios, and a 200mm F4 photax. Both work with the camera pretty well, but I'm kind of lacking the same sort of wide angle that I can get with the 20mm lens on my praktica. I know that to get the equivalent to that on the gx7, I'd need a 10mm lens, which isn't exactly common outside of dedicated M43 lenses, however, since my budget won't really stretch to that, even second hand (Uni student) I'm looking for alternate ways of getting that sort of field of view from what I've got. The cheapest option looks to be getting a wide-angle converter to screw on to the end of the lens, but I'm not sure how they tend to be on quality. A "Speed-booster" type 42mm adapter would be the most versitile choice, but they're expensive yet again, and the "cheap" versions on ebay tend to be more like 0.75x rather than 0.5ish, which wouldn't give me that much of an advantage. Does anyone have any recomendations?

Additionally, does anyone have any recomendations for compact lenses? It's not exactly crucial, but it'd be useful to have something close to a pancake lens that I could use with it, for the sake of convenience; The same desire for not spending much money applies.

Thanks in advance for any assistance; Appologies for being the kind of annoying student who doesn't want to spend any money on anything, but unfortunately that's kind of what I am.