Hi folks, I'm considering buying my first Blackberry - want to keep the costs down. Maybe you can help me out...

I was all set to order a Curve from O2 - money is tight though and that £60 up front plus £35 a month for their 18 month plan with Blackberry Unlimited Internet is quite steep (I already have a company mobile you see - so I'm paying for something myself I want rather than need). However I see that Vodafone are doing it for free on a 300 min tariff, with half price line rental for 6 months. However on the consumer side they list 120mb Mobile Internet solution at £7.50 which seems reasonable... £21 for 6 months, free phone, then £34.5 for the following 12 months. I'm guessing however that I don't get push email for that... would I be able to use it with pop email, and configure it to check for emails every 10 mins or something? Or am I better to go with the O2 deal?