Nemo
That is not a bad price at all for that kit. One thing I would do is instantly replace the Bolt (not entire BCG). I have seen at least 3 of the AR Stoner kits that have had bolt failures. The ones they are using are economy (thats how they keep the price of the kit down) and are not Magnetic Particle Inspected (MPI) or High Pressure Tested(HP). They are splitting right at the pivot pin.
The same thing has been common in Ghost, Anderson, Radiacal and a number of other "low cost" options that are out there. You dont NEED to replace it immediately, but I would have one ready to drop in.
Chris