Humm ... I know that Central Market doesn't carry only USDA prime grade meats - so I talked to one of the butchers while I was there a little while ago. They carry both Choice and Prime (no Select - I thought he was going to call security to escort me out of the store when I asked about it) - choice is about $5/lb cheaper ... but $25/lb still isn't cheap!
So, I called my favorite butcher who works for a WalMart Superstore (my son) and checked on what they have. A full beef tenderloin is about 10-lbs and runs about $9.50/lb. But, they also have 1/2 tenderloins (from the small end - the end you cut tournedos, filet mignons and tip from) that are about $35. Call and ask what they have .... ButcherBoy said not all stores carry the same selection - but they can special order things for you from the distribution center if they don't carry what you want.
Another thing I was thinking about, and ButcherBoy brought up, look in the meat department where they have the packaged meats - specifically look for tenderloins in cryovac packages. These will be either Choice or Select grades (read the label).
One last thought, knowing San Antonio and my area, look for a grocery store in a predominately Hispanic or lower income area ... they will generally carry Select grades.
"It ain't what you don't know that gets you in trouble. It's what you know for sure that just ain't so." - Mark Twain