I have to agree with the BOB stroller suggestion! Of course, I am partial to the Stroller Strides Fitness Stroller because we took the time to create the special features with BOB that so many moms desired but no other stroller had. BOB is a great company and their strollers are light and very durable. I do completely understand the financial concern. It will be an investment which will last a long time! However, there are other sources, ebay was motioned but I would check out Craigslist, as well.
Hope that helps : )