Way back when we were less well-off, I used to take ketchup and mustard with a bit of olive oil and use that as BBQ sauce. Basically, hot dog condiments. Sometimes, if we had relish, I would throw that in, too. Over time it evolved to include a bit of balsamic vinegar, maple syrup, and lemon juice.
3oz ketchup (Heinz 57, please. No imposters!)
1oz mustard (prefer real Düsseldorf style, but any ground mustard will do)
1T olive oil
1T maple syrup (or more!)
1T balsamic vinegar
1t lemon juice
salt and pepper to taste
1T tomato paste if you are using crappy ketchup
This is enough for about two pounds of cut up chicken breast. Mix it up, soak the chicken for 1-2 hours, then throw on grille until the edges are blackened. The blackened edges are sooooooo yummy!