You can buy "reading glasses" from a supermarket in Britain for $4.
They might be OK, but custom lenses will almost certainly be better.
(Also, glasses ordered online in Britain start at less than $10 a pair. Once something purchased that infrequently costs less than a McDonald's meal, there's not much pressure to further reduce the price. It's one hour work at the legal minimum wage.)
Here in the US I could buy reading glasses in a pharmacy for less than $10 (several variations). They come in a range like -2.0 to +2.0 in increments of 0.25.
I don't wear glasses, but I suppose I did I could get something that roughly works for me for a price of a coffee and a couple of doughnuts. These glasses don't look cool, but don't look ugly either, they are just extremely basic. Likely fine for reading at home.
They are also on Amazon. There are folding reading glasses that go from 1.0x to 4.0x that are $15 for 2 pair. I keep one on me for really tiny print. It even survived ending up in the washing machine.
They might be OK, but custom lenses will almost certainly be better.
(Also, glasses ordered online in Britain start at less than $10 a pair. Once something purchased that infrequently costs less than a McDonald's meal, there's not much pressure to further reduce the price. It's one hour work at the legal minimum wage.)