I started purchasing modulars with the Emporium. I was lucky enough the green grocer was still relatively cheap on BL then, but the Market Street and Café Corner had long since retired. I purchased a used MS from bricklink for about $500. I drew the line with CC and decided I should purchased parts instead. CC was the last building I completed in my modular collection. I just finished last year after couple of years I've been parting out the set on BL from no less than 20 sellers.
The most expensive piece was the 2x4 white window frame on the third floor. They were $5-$10 a piece. :O
My advice would be don't hurry to finish the set and never buy just a few parts at a time. Set up a want-list for your CC, as well as other parts that you're waiting to get. Try to consider cheaper alternative parts and I don't mean colour substitution. Find a seller that has more parts you're looking for rather than the cheapest. Chances are the seller who has the cheapest parts may only have few parts you are looking for.