the price seems a little high. My HLT is a 13.x gallon imperial keg. I got it from the LHBS, the guy there charged me $25 to weld on all the fittings I wanted, and $0 for the keg.
Also last year, I got two 15.5 gallon sanke kegs off craigslist for $20-25, so only $10-12 each. The most I've paid was $30 for a 15.5 gallon to my old boss.
Another point to consider - unless you're using some sort of foam control, those smaller kegs won't work well for the boil kettle. I think beersmith says my normal pre-boil volume for an 11 gallon batch is 13.something gallons. I have to pay attention to prevent a boilover, even in the 15.5 gal