You can google b a sauce recipes but unless you're going to start with raw ingredients this is poor advice (most recipes just have you mix several other condiments).
I'd suggest that you look for BBQ sauce with no sugar added if that's a concern. Personally I'm not worried about 10g of sugar in 2tbsp of sauce (45cal, this is regular old kraft bbq sauce) but recently I bought a bottle from Costco that only has 5g and still tastes awesome.
Mustard is good advice though. I have 7 different types of mustard right now.