I agree with the other guys , go big or save your money longer until you can buy a big one . you will not be happy with a small grinder .
I have a home built one , it works great . it's a #32 grinder that I had belt driven with a electric motor from an old clothes drier . that drier motor wore out so I bought a new motor for it . it's 1 hp . this thing does grind now . I can't find a pic with the new motor and all put together , but I do have a few pics to show you . when I updated the motor I also raised the grinder so I could put a deeper pan under it . the way I have it set up now it really works well . I'll guess at todays prices , you could build this for under $300 . if you're handy building things this is another option .
EDIT to correct motor HP