That's a tough question. Do you have any other special needs beyond small folded size?
Are you looking for a stroller with bigger wheels for the outdoors (i.e. the quinny buzz you referred to has bigger wheels)
Umbrella strollers fold super small, but tend to be a little flimsy.
This one however is a little sturdier and has great reviews:
The Stroller Superstore: Standard: Graco IPO Stroller - Platinum
Doesn't hurt that it's cheap.
If your looking for an outdoor stroller that is super functional I highly recommend the BOB revolution. Though to use it with an infant you'll need to get the carseat adapter. And it doesn't really help your budget problem.
Stroller:
The Stroller Superstore: Joggers: BOB Revolution Stroller in Mesa Orange
Carseat adapter:
The Stroller Superstore: Joggers: BOB Infant Car Seat Adapter For Single Strollers
Now.. as I'm thinking this through while writing the above, I realized you might really, really like a Baby Jogger City stroller:
The Stroller Superstore: Joggers: Baby Jogger City Mini Single Stroller - Black/Black
It isn't really a "jogging" stroller as the front wheel doesn't lock. But it's highly functional, light, folds really small, etc. (the biggest part of the BOB above when folded is the wheels, if it had smaller wheels it would fold incredibly small).
Just like with the BOB, youll need a carseat adapter for the infant stage:
The Stroller Superstore: Joggers: Baby Jogger Car Seat Adaptor
Hope that helps.