A quick look on the interweb shows that you can get a WX-350 for less than $1000 with free shipping. That's a good deal on a big tank. I do not consider that expensive.
Almost anything that TSC sells with regards to water well equipment should be considered big box junk. The TSC tank will probably only last about the same time as the warranty, but you normally won't notice exactly when it goes out. TSC does sell a regular galv. tank but you really need one with a bladder.
All you have to do is "T" into your existing piping. You only need one inlet/outlet for the tank. Set the bladder pressure 2 psi below cut-in pressure and you'll be good to go.
In one of your pictures you show about 8 joints of drop pipe. How many joints total did you have out of the well? It looks like 1.25" pipe also. Since you used a franklin motor it is unlikely that you used a Berkley pump since Franklin/Pentair do not use each other's pumps/motors as of 5 years ago. Of course, the driller can mate up whichever motor to his pump of choice but most order the pumps/motors from the same supplier (anything above about 2 HP always come separate anyways). I would like to know the exact model of pump and how many GPM it is rated for.