Can I buy a set of strings that only has one size?

I usually buy my husband's guitar strings online and he wants more strings. Problem is, he keeps breaking the smallest string, he has a couple sets of strings, he just keeps breaking the smallest one. So can I buy strings that come with 5-10 strings of just that one size? I looked on Amazon, I usually buy him Ernie Ball super slinky acoustic strings and I don't see anything like that with this brand.