Keeping costs down with prepaid plan

[neit]

I currently have Sprint SERO plan which runs $45/month and think I can save a lot of money by switching to a prepaid plan. I'm almost always at a wifi area and currently have google voice integrated with my plan (ie, only one phone number). Sprint also seems to have a hard time working correctly with my old phone.

I have a GSM android phone and got a $50 prepaid sim from platinumtel (good for 6 months). Ideally I'd use GrooveIP when I have wifi and to use my minutes when I'm not there. Since I've used my GV/sprint number forever i was planning on porting that to GV when I close my sprint account.

My concerns are as follows:
GV can't do MMS, if someone sends me an MMS message, but I have text forwarding set to off (since I use GV app), will it still be forwarded to my phone?
Anyone have any idea on how much data GV app uses for text messaging? it's 10cents per meg or 2 cents per text, when out of wifi range I'm not sure which would be better to use
Are there any general settings to keep my cell radio usage down to a minimum to stretch out my prepaid card?

I'm new to prepaid plans in general, would appreciate any links or other resources for more information.

 

[Gooberlx2]

Honestly, you're not going to save much anywhere without going to Tmo's $30 prepaid plan.

If the SERO plan and Sprint coverage provides what you need, I'd probably stick with them. Can you upgrade to a new phone?

 

[cronos]

Honestly, you're not going to save much anywhere without going to Tmo's $30 prepaid plan.

That is highly dependent on the amount of minutes/txt he's expected in using.

What is your average usage, OP? At least the minutes/txt. If it's really low then any kind of monthly plan will be a waste and his choice of the pay-to-go plan is correct.