I had a 1986 Ranger with a 2.9 and 4x4 regular cab long bed. I made a wood frame canopy with a heavy tarp pulled over it. Worked great and was really cheap and easy to make. The frame was removable. I had cut down 2x4s to fit down into the stake holes at the 4 bed corners then connected 2x3s front to back on the sides and across the front and rear of the bed and the central span with 2x2s crossing side to side 16" oc. To prevent rain pooling on the roof, I put a 4x8 sheet of 1/4" plywood. A futon bed fit perfectly between the wheel wells and I could roll it up when not in use and stuff all my stuff in there. At camp, the stuff came out and got set up. The bed rolled out and the tail gate left down, up at night. The roof plywood hanged out beyond the down tail gate so in bad weather, the tail gate became a dry place to hang out. To make it darker and quieter inside I started putting an old comforter on the canopy frame then the tarp over that. I put ropes from tie downs over the top side to side to hold everything down when traveling. Made a great camper and I could go back packing a couple days into the woods then come back and have a nice place to stay for the rest of the trip or just stay at the truck and have a nice trip.
When you're young and poor, you find a way and I did.
Thank you Mother of Invention.
Or, you can try to find one of the old S&S campers that was designed for those smaller S-10 and Ranger trucks.
Good Luck.