Rent it. When we swapped bodies on our Mack, we sandblasted the new body, frame, equipment trailer and what ever else we could find that needed it around the shop. We just simply rented a 1050lb pressure pot type blaster and the 185 fcm IR jackhammer compressor to run it from the local rental center. The "kit" had the 150lb or 300 lb pot, the 185IR and 50' of hose, the airflow hood and pump and heavy gloves for $200 a day. We shot every thing in one day. I want to say sand ran $8 a 50lb bag and we probably went thru 150 lbs of sand maybe a bit more.
Most small sized pot type sand blasters need a good sized volume of air to run them, usually 15cfm or more at 90+psi. The bigger ones require a big tow behind compressor. Most guys really don't have the air volume to run even the small ones.
I'll probably end up renting one to do both the plows this summer and posibly my buddies small trailer and a few other odds and ends. It will probably take longer to set up each piece to shoot than it takes to do it. I doubt everything I plan to do will take more than 2-3 hrs tops, and by doing some of his stuff at the same time we can split the costs and save. Then while I'm running the blaster back, he'll probably set up the spray gun and start shooting everything with primer.