My vote is for Stubb's Spicy BBQ Sauce. I used to spend hours making my own and since you can't make just a little I always had more than I needed or would use. The only time I use BBQ sauce is on pulled pork sandwiches and I only do pulled pork once or twice a season. After I gave Stubb's a try, I never made BBQ sauce again.
Gates BBQ or Jack's Stack. Both available online (I think), though that may defeat the purpose here. KC Masterpiece is also another good one. What can I say, I'm a KC boy who loves his KC style BBQ.
Commissary stocks the usual suspects. Ray's is the house brand at our facilities, so I'm getting burned out on that. Tried the Stubbs a few times...not bad at all. I'm currently using Corky's with a little of the adobo from canned chipotle mixed in for more depth of flavor. Amazon is always a purchasing option.
If I were smart, I'd open a Trader Joe's on this island.
I add thai sweet chili sauce, and then start hunting for bottles of condiments that are running low in my fridge.
I have added jams and mustards, the last bits of 4 catchup bottles ....
then I look for some of the usual seasonings pap, oregano,
TASTE OFTEN AND ONLY ADD A BIT AT A TIME!
But I always add a fresh onion finely chopped
* this method has even come in second place in a regional comp.