I have some experience with economy 1911s, having worked on a couple for friends. Hands down, I would say that the most reliable that I have handled is the Rock Island Armory line. The tend to be a little on the loose side like the government issue Colts of the pre-M9 era, so they won't be the ultimate in accuracy, but they go bang every time you pull the trigger on a hardball cartridge. They are extremely close to "spec", so if you decide to customize it, most aftermarket accessories will fit with no problem. They are not pretty, but they work.
The Taurus line is mighty attractive in that it has the common customizing features that many 1911 shooters want. My limited experience with them (two guns - a 45ACP and a 38 Super) tells me that they want to be broken in with around 250 rounds, and even then may take a little tweaking to become reliable enough for self defense. The weakest spot seems to be the magazine, but that can be solved with aftermarket units. The other symptom I found was that the feed ramp gap between the frame and the barrel throat is too small (in the 45) or non-existant (in the 38 Super). Once I removed enough metal and recontoured the chamber throat, both guns ran fine.
The least expensive 1911 I own is a Norinco, which was purchased for $299 about 20 years ago. You will pay that much just for a Norinco frame these days. If I were building a gun for myself, I might consider an RIA frame from Sarco, and fit it with components of my choosing. I might consider the Taurus in 9mm or 38 Super, just to play around with.
An alternative 45ACP, if you want a steel pistol is the EAA Witness. This platform is based on the venerable CZ75 design. They tend to be durable and reliable and have a double stack magazine. EAA sells several configurations across a broad price range. I picked up a used Witness Full Size without a rail in a pawn shop last year for $300. It has been a lot of fun for about 1000 rounds with no problems other than having to drift the rear sight to get it to line up on target.