if your prescription is not abnormal(if you don't need special lenses), then you should expect a low price on glasses from them.
you can only do a virtual try-on, which sucks (i want to make sure it fits my face comfortably)
you mention low quality frames, I bought the $30 frames a couple times from there. They lasted me a while, but the frames did feel cheap--flimsy. I made sure not to fall asleep with them.
if you are tight on cash, you wear glasses daily, and don't mind the colors, I would buy one of the ~$30 range pair that you like. Once you get them in the mail and know they are ok for you, buy 2 more pairs as back up.
google online glass stores. There's coastal, zenni, and warby parker, right of the top of my head.
when i buy glasses again, it will be from warby parker. they are more expensive, but I know from my friend who bought them that they last and look great.
zenni and coastal are kind of similar. look for coupons/sales. they had a bogo/ 2 for 1 deal when i bought, not sure if they still do this.