Your best bet is probably to contact a supply house like Sargent-Welch or Fisher Scientific. If you specifically want glassware, you could try Ace Glass or Wilmad. Note these aren't places in Dallas you can just walk into ... you'd have to order them.
wallmart
You can purchase test tubes from a science equipment magazine. They will be available in any good stores. Also you can go onto eBay to buy some test tubes.
Indigo Instruments offers a variety of science equipment, including test tubes, at its website, Indigo.com. Standard chemistry lab test tubes are 70 cents apiece.
Test tubes can be bought in special stores that sell educational or medical supplies. Some educational and teacher catalogs also sell them. Some universities also have student stores where you can buy test tubes and other lab equipment.
You can go to your local Radio Shack in Dallas for surveillance equipment. They usually have a good selection.
Advanced Test Equipment Rentals, since 1981, is the largest leading equipment dealer carrying a variety of equipment. check them out on line for NEW and USED equipment!
Science test tubes may go anywhere from 2 dollars for a pack to 100 plus dollars for a single tube. It varies on the type of test tube you are looking to buy.
If you are going to buy sued exercise equipment, just make sure it does still work and have a test on it before you buy.
The best place to find a wide variety of used electronic test equipment in the US is on the internet. Some companies that sell this type of equipment include Electrorent, Metric Test, and Recon Test.
You can order them from any number of suppliers of glassware. Two common ones are Fisher Scientific and Ace Glass. If you're looking for a store that you can actually go to that sells them, you might try a hobby store; they're sometimes sold as miniature flower vases and a few hobby stores have an actual chemistry section.
It is possible to purchase electronic test equipment at electronics stores such as Best Buy and Visions Electronics. It is also possible to purchase it on Ebay and Amazon.
You can go to your local Radio Shack in Dallas for surveillance equipment. They usually have a good selection.