Reliable stores to find Pokemon cards?

Hi! I’m home for the summer from college and I’m trying to find pokemon packs for my boyfriend for a present. It’s so tough finding any pokemon anywhere in stores they’re always out of stock! And I’ve been to a couple card shops but it’s hard to justify paying 3-4 times the base price for a bundle, like I just can’t justify paying $70 when pokemon center sells them for $27. Any help would be appreciated! I just wanna be able to surprise my boyfriend without breaking the bank