Stroller for 4 month old

Au

I need help on a stroller for a 4 and half month old. He doesn't sit up yet but has really good head control. I want something light and something that isn't too pricey. I am going to mickey's not so scary halloween party this Sunday. I usually just wear him in a sling but never for this long so I would like a stroller I could put him in when I need too. Could a light umbrella stroller work?