I am interested in having web based email (Yahoo/Gmail) pushed instantly to my bb while also sync with my blackberry and desktop outlook. How much should I expect to pay and what service am I asking for?
International BES (OP didn't ask for that) clocks in at 65-70/mo (add taxes/fees, then you are over 75/mo). We have to pony up for that for about half of our users due to travel (lucky us!).
Using your figures 45+35=80. I got a sense that the OP asked for a bottom line price. I think I was close in my estimate (unless someone knows of $10/mo hosting service). I just wanted to prepare him for the shock that a 20-30/mo BIS plan probably won't cut it (unless Yahoo or Google gets their acts together).
You can get exactly what you're looking for from a hosted Exchange provider. We use Intermedia to host our Exchange and they have been great so far. They can push email instantly to your Blackberry or other device so there is no downtime. It's not that expensive either.