Won't find anything decent under £120 new-ish.
All G36s have fiddly battery compartments. I've got around this by using crane stock batteries and taping them either side of the barrel. You have to charge the battery with the gun alongside but it means you don't have to worry about messing around with fitting the battery in. Just slide the foregrip back on and away you go.
The SRC would be the cheapest, but i'd recommend getting the Gen III, not the Gen II.
P.s. Since when was "blood and sweat" equal to £120? :L
Haha lol, i see how you got that.
But yeh, i originally got the DE M900A for £120 but a few months later the gear were all worn out because they were plastic so I got new gearbox set costing £20 to fix the gears and fitted a new piston and bushing into it. But it still has a plastic frame and tappets.
Then it didn't feed very well because the sector gear didn't pull the tappet far enough fire a bb pellet, so i had to trim the nozzle a bit to compensate for it. So then it only worked in semi auto.
Then the some of the hop up split and broke a bit and was a bit iffy.
Then eventually the anti reversal latch gave in and broke, so bought a new metal one. When firing the fixed and modified gearbox, it didn't sound great with all the gears meshing together but it was better than nothing, so a semi auto AK for about 3 months.
Then came my birthday which I got a new CYMA hop up (£4), a brand new CYMA CM02 metal gearbox (£40) and installed it in but there was a problem. The hop up chamber itself didn't fit into the gun so i had to use my old hop up chamber and fit some of the CYMA hop up internals in it. And even that didn't fit into the gearbox and I had to trim it again until it fit in.
The gearbox itself didn't fit into the AK frame and I was so pissed off. I had to trim some of the AK interior until the gearbox finally wedged in enough to close the cover and everything.
But that's not all. Since the wiring of the new gearbox went to the stock and not in the dust cover, I had to completely rewire the whole battery compartments in my technology centre using soldering irons and wire strippers.
When that finally was done I got a new 9.6v nun chuck battery (£40) because the 7 cell stick battery that came with it was too long to fit in the stock.
When all of the above was done, it was finally complete. It is now working perfectly and can achieve 1000 rpm. I had spent so much time fixing it. And all the gearbox and hop up parts and metal gearbox I bought was from my own money and made me broke.
And if that's not worth £120, IMMA RAGE!
