Brandon,
The specs on the bid tex show the tire rating as a B rated tire. Not good.... The trailer is a 6K trailer, with two 3,500K axles that 7000K total weight for the trailer weight itself and the load it will carry. I am assuming that the trailer weights around 1500LBS. If you load you 6K blazer on the trailer it will weigh in around 7500 lbs, it's about 1500 lbs over the trailer rating. Now keep in mind what is posted eariler, that every trailer manuafacture under states there trailer, due to liability reasons, the don't want to push the limits of the design because it puts the responsiblity on them if a tragic accident happens, so the understate them. If you speak with the sales guy at Big Tex, and tell him how much the blazer weighs he will cry and moan and try to sell you the bigger trailer, and then he will give you the whole "I won't be responsible" talk.
Here is the what I reccomend. On the trailer you are lookin at, check the max tire pressure vs. the total weight the B rated tires show on the sidewall of the tires. Take that weight amount and times it by 4 if it's over 7500 lbs you will be ok. I'm almost sure it won't be over or even at 7500lbs when you add it up. If they don't add up. Then try to get the sales guy to upgrage the tires to either D or E rated tires. They will hold the load. Don't get into a pissing match with the sales guy, just tell him you want' either D or E rated tires. Don't tell him how much you are going to tow. If he tell you they are rated for the trailer, tell him you don't care you want D or E rated. The D or E rated tires will make a huge diffrence!!!!! They will also not get as hot when you are towing and help with towing a little over the trailer weight.
The other thing I am going to tell you will make all the diffrence in the world with your towing especially with a 1/2 ton rig/tow rig. By a rated weight distributing hitch!! They run around 250/300 bucks. It will be the best investment you will every purchase when you are towing with a 1/2 ton rig. It helps transfers som of the weight off the rear axle and onto the the front axle. It rides better, it does not shoot your headlights into oncomming traffic, and it helps control sway. Don't even debate this purchase, just do it. It will be the best money next to a trailer that you will ever spend. Hell I use mine with my 1 ton dually it works so nice. It's designed to make you life much easier and much SAFER.
Go down to Sams club and buy youself 3 2" wide ratchet straps, and you are set.
Make sure your tow rig has a trailer brake controler, and wire it up. And you should be set. Also make sure you hitch is rated for the weight.
If it was me and I was looking to purchase a trailer, I would get the tires upgraded to D or E, buy a weight distributing hitch, and see if the dealer will add breaks to the second axle for a small fee.
Other than that I would probable go for it. 900.00 is cheap for a trailer here in AZ.
The cheapest I have seen them for here kinda like the same you are looking at is around 1600.00.
Let me know if you have any more questions, I'm not the expert by any means, but I have done my fair share of towing in my wheeling days.
Rob