They are really not that expensive. The 6" was $65 and the 4" was like $50ish.
By the time you buy the caps ($15 for 6" PVC cap), the glue, ($2), the female threaded adapter ($12) and threaded cap ($5), you still need the hardware for mounting it ($5?). For an extra $20 you get a nice looking setup that is lockable. My carriers did not come with screws or holes so I had to drill my own and I used rivets. Not a big deal. Makes it a little more secure because you can't just unbolt the caps and take them now.
Best of all, since I was paying for the truck stuff, I just put it on the company credit card :D
When I get home, I may experiment with flipping it over so the strut isn't hanging low.