I bought mine a while ago, but at today's prices, this MT-01C set is $309 unpainted. You'll need at least 3 of those ~$55 sheets of aluminum, plus gaskets, 4 locksets, and whatever other supplies. So you are paying about $78/bag in this 2 bag set for that extra hardware, Wendell's labor, experience, and jigs. Maybe you are good enough to get yours right without scrapping the first set and have the time, but most people need to make parts a couple times to get them right. (One reason kit planes are so much faster to build than scratch built.)
Even so, I've not priced luggage in a while and your $800 was a surprise. But especially on a teacher's salary, I see how you got there and the issue.
I watch for scratch & dent & clearance, and am pretty sure I paid something like $230 for my rack set at TwistedThrottle's Clearance site, so was surprised at the new full retail price of $325. That brings a 2-bag set with racks to $625, which is way less than the competing off the shelf welded aluminum sets. Add for the third bag and I see where you got your $800 figure. Of course, when you sell the Tenere, you can re-use the boxes or sell them to recover probably 1/2 at least.