I was fortunate enough to pick up my M4 Bushy Carbine, new for a decent price because it has an A1upper. Like you I wanted to dress it up on a budget. Heres mine and the progression of change......oh I went way out of the budget on the last purchase:
Used MagPul Raid Grip
Used Knight Armament RAS front grip with panels and vertical grip
El Zetta Front Sight Base weapon light mount
Seven 30 round Pmags
UTG picatinny rail mounted bipod
1500 rounds of assorted ammo
EOTech 512 Hologram Sight system
Now I went and bought a 22cal A4 upper and three 22cal AR Mags from Velocity, I have yet to install and shoot.
