Cons: Basically a 1 person ski, forget towing, or passengers. You didn't mention year but probably early 90's, will be well worn. Don't buy unless you are good mechanically. It will need constant maintenance (carbs, cleaned/rebuilt) etc.. Has all the problems with early 2 stroke engines. Definitely check compression before you buy........many will need top end rebuild at this point. The blaster is not a stable ski by modern standards, and is difficult to re-board in deep water. I'd compare the ride to a dirt bike. Bouncy, wet, and playful........not something your mother-in-law would enjoy.
Pros: Cheap. $1000 is good price if everything checks out and runs good in water. The 700cc engine was popular on other skis, so you can find parts......and you will probably need to eventually.
Bottom line: OK ski if you are mechanically inclined, and looking for something to play around with solo.