Which currently free services you use would you pay for?
Of thr free services you use, social media, YouTube and some streaming sites, mail maybe, what services would you pay for and how much? What expectations would you have for said paid service?
Gmail. If that can guarantee support from google.
Twitter. It's a fantastic user acquisition channel. I don't know how I would have gotten early users without it.
Metroretro if the pricing is reasonable (unlike conceptboard)