Will I be charged for WiFi ththering if I start the service on my phone? Not having that in my data plan.
Robbie is correct that you won't be charged for wifi tethering. However, you should have tethering in your plan if you intend to use tethering. If you wifi tether without the $29.99 add-on, it is against the Sprint Terms and Conditions.
Examples of prohibited data uses: (vi) for an activity that connects any device to Personal Computers (including without limitation, laptops), or other equipment for the purpose of transmitting wireless data over the network (unless customer is using a plan designated for such usage)
Sprint doesn't actually support tethering anymore. I used to have the option as phone as modem and they discontinued it over a year ago.
You can still use wifi enabled hotspots on the EVO, Evo shift and the Samsung epic but you have to have wifi hotspot option added to your plan which is $29.99 a month.
Simple tethering with a usb cable or wifi directly to any device without the wifi hotspot option is actually a violation of the sprint TOS.
read the fine print in your contract.