look for a non runner lt 80 (if you want to stay cheap and small so he can upgrade to it later)its always fuel or the pullstart

i bought a minter chingchong 1 for £70 and the oil had turned to glue, forced it to start got it hot changed the oil to super S and its been perfect since, pissed over our lt50 and i can ride it for ever on 2 wheels

i had a quadzilla and the quality was piss poor £100 paid £200 sold 2 weeks later

maybe a off roads buggy, theres a fair few about