What engine and trans do you have? 2wd or 4wd? Do you know what axle ratio. All of these things affect the rating. The 1500's when properly equipped have a max tow of 7300 lbs. How far do you want to tow and over what type of terrain? If your blazer weighs in around 5500 then you can go with a 7K trailer. Usually $2500 new. If you are over that weight a 10K trailer would go for $4000. Best bet would be to weigh you blazer when you have the axles in and look for a used trailer locally. Usually cost 1/2 to 2/3 of a new one.