Is this an emergency or can it wait?

My dog has been constipated for the past couple days, only 2 bowel movements in the past 3 days. He normally has about two a day. Today he was incontinent with his bowel movement and then vomited three times. The first time he vomited it was brown with a smell of feces, second time had a little foam in it and the third was just foam. Since today is Saturday and Fourth of July is on Monday the soonest I can get him in is Tuesday at 9 a.m. I could however take him to the emergency clinic however it costs $100 just to walk into the door. He is also taking water.