Best to hold out for a mackissic, even if it takes a few months.
But, buy it for the right reasons. Even if the entire block donates their trimmings to you, it will still be like 1/10 of what a tree trimmer can dump in your driveway in 15 minutes, and you'll have spent an entire day and 5+ gallons of gas to chip it.
I have the top end commercial mackissic (retails for like $4k), and I can chip full cubic yard in maybe 2 or 3 hours? Your typical tree trimmer will carry 10 to 15 yards in a load. The guys with the custom aluminum beds can dump 25+ yards in a load. So, a single load of tree trimmer mulch will save you somewhere around 50 hours of work and 30 gallons of gas. Unless your time is worth less than 10 or 20 cents an hour, I would suggest just calling a tree trimmer once or twice a year. And, trust me, running a chipper for 3 hours is a lot of work. I'm in pretty good shape, and 3 hours of the chipper will have me beat, especially during the summer heat.
If you're going to get a chipper, get it for the following reasons:
a) You feel bad about chucking biodegradable debris into the refuse stream
b) You have so much debris after a trim that it's not feasible nor easy to set it out by the curb