I live in 23059, too, and bought my daughter a mattress from Haynes (the Dump is owned by Haynes, too.) We bought a Paramount Dr. Maas mattress last March, and although 10 months is not a long period of time, the mattress seems to be holding up well for my petite daughter at 109 lbs. There is minimal indentation and the mattress is , for her, the most comfortable she has ever slept on. Sure, no one knows the exact components of the layers, but if it lasts through high school, 5 more years, it will be a bargain. Original Mattress Factory on Broad St made excellent mattresses, only slightly more expensive, but daughter wasn’t as comfortable. See this post:
https://forum.mattressunderground.com/t/innerspring-mattress-for-a-teenager-in-richmond-va
Good luck!