How to buy cheap/disposable/nonprescription/generic reading glasses in China?

Even though they're in a tough case, my reading glasses were broken when I pulled them out to fill in a hotel registration form a couple of nights ago here in China. My previous pair was nicked by a street kid in Vietnam, the pair before that I lost somehow in Japan on another trip.

^Dammit!

Because they are liable to get lost, broken, and stolen I like to buy cheap generic reading glasses. So far I've always bought them at Japanese discount store chains (100 yen shops) such as The Daiso.

^{The huge range in a branch of The Daiso in Ho Chi Minh City.}

• I don't need prescription glasses. I only need magnification so I can read.
• I could not care less about fashion. Ugly frames are great.
• My Chinese is terrible. I'm not sure if 老花镜 (lǎo huājìng) is the everyday word for reading glasses or overly technical jargon like "presbyopic spectacles" in English.

I've looked in glasses shops but they never have English speakers and even the prices are confusing. There was something labelled "1 yuan" in one shop. They have things like two-for one deals. I don't even know if these places deal in non-prescription magnification-only glasses.

I've looked in discount shops with random junk but if they have anything close it's only magnifying glasses, and it turns out gorilla arm is a thing.

There are cheap sunglasses and "fashion" glasses sellers. The latter have glass that is either flat or otherwise doesn't alter the optical properties of the light. Ie, they are not really lenses.

I don't have a local friend to tag along and interpret for me.

Is there something like The Daiso in China? (I'm in Nanning heading to Guangzhou in a few days.)

If not, can glasses shops make really cheap reading glasses (a few bucks) and if so, what Chinese might I need to get through the process?

^{Help me be able to use my Chinese dictionary again!}