Thank you for your comments about my glass block. It was fun to make, and I think they are so cool. I got my supplies at AC Moore, but this is probably something you can find anywhere, all year round.
I did find a couple places to buy the decals if you go and your craft store doesn't have what you like.
This site has some religious and non-religious decals.
And Etsy. I forgot, Etsy is more than just an online craft fair. I normally don't buy crafting supplies there, but I think this one is so pretty! And there are links to other people selling other decals.
You can also look on Pinterest for ideas of what to do with the blocks. They're pretty affordable all in all. I don't think I paid more than $10 for the block and the decal. Lights, of course, cost a little more (maybe I should have posted this before Christmas, so the lights would have been on clearance), but it's maybe $20 for the whole thing. All in all, not bad.
Meari had asked about the other charts in the series of PS Samplers my WIP is from. I took pictures, but Blogger is acting up right now, so I'll try to post them later.