Im on both sides of this story.
On one side it sounds expensive, but on the other side its very reasonable.
I used to work at a fab shop down the road until I just didnt have enough time to do it.
First of steel is rediculous these days, and most places wont let you walk in a buy a little piece of it. But If you know where to go you can get a small piece.
2nd. Even guys(like me) that are set up with a $2,500 Millermatic 252 welder(.035 wire), still can barely weld anything thicker than 3/8, and thats pushing it. Now I will say that you can set up your 252 with .045 flux core and weld 1" plate just fine(what I did). But spools of weliding wire aint cheap. Where I worked we he had a welder set up with .045, but he also had over $10,000 invested in the welder sitting on that cart.
Beveling costs a lot too, if you dont have a beveler, you can spend A LOT of time grinding it down. Keep in mind time is money.
alos, you can have the best welder in the world but if you cant weld, its useless. Welding isnt for everybody, and even if your weld looks pretty, cut it open and you may be surprised that you barely penatrated.
what im trying to say, is that, these guys prices are reasonable. But if your set up at home and can weld, you can do it a lot cheaper.
Heck if theres this many people crying about it maybe ill make a few extra hitches and sell them for the pennies I put into it, no labor, and make people sign a waiver that says im not resbonsable if anything happens.
Sh!t aint cheap these days.