If a company can afford to pay 10 full-time employees, then $4990 isn't a major expense (of course, neither is $499 for a single developer).
As for CALs themselves, I think you need to contact a reseller for those. I get my SALs (similar, but different) from Insight UK. Insight do TFS SALs, but I don't know about CALs because I can't see them on their website or by searching for them. Give them a ding: http://uk.insight.com/en-gb/information/contact