You can substitute vanilla extract, vanilla bean paste is more of a specialty item found in baking supply stores or online it’s readily available. It’s thicker than extract and has the bits of the vanilla bean itself, it’s really delicious so if you do see it pick some up! It all depends on where you live and what stores you have close by, I am able to find it in lots of stores near me, but I do frequent baking supply stores it’s not a typical item someone would find in a local grocery store. When selecting vanilla extract go for a great high-quality vanilla in baked goods, it makes all the difference in flavor, Neiman Massey, LorAnn’s, MexicanVanilla.com, are all good, check amazon for prices too.