"Quiero comprar unos zapatos grises."
Translation:I want to buy some gray shoes.
We live and learn. I didn’t know you could spell grey with an a! DL accepts both now.
"I want to buy grey shoes" is the better answer, you can't always translate unos to English, it is a plural indefinite article, something that English doesn't have.
The implication of both unos and some in this context is that you are buying a pair of shoes. 'A few' doesn't imply the same.