Hello tasha3--  Remember that you get what you pay for.  The useful site, www.carcomplaints.com, does not indicate any characteristic problems pertaining to this model that you should fear.  However, at this price I suspect the Blazer is in less than perfect condition and perhaps the mileage is high.  I would suggest you have a mechanic do an inspection for you.  The cost of the inspection is usually quite reasonable and it can pinpoint any big bucks repairs the Blazer may be facing.   Good luck from Bovan.