I agree with Lindbergh Lendl S. Soriano points,
According to my experience,Prepaid plan is the best option for who are using cell phone rarely.If you aer interested to get prepaid service,Try to following tips to choose prepaid plan.
• How good is the coverage area where you plan to use the phone most?
• Are there any activation fees?
• Are there expiration dates on the minute cards?
• Are anytime minutes more expensive than nights and weekends?
• Is long distance included?
• Are there roaming charges?
• Are there charges for features I need?
After getting your prepaid plan,Make sure your current phone is accept that carrier,If it's locked by single network means,You will need to unlock it to work with your new prepaid Sim card.For unlocking you can approach your service provider or else try to buy an unlocking service from any one of the online unlocking service provider like TheUnlockSpot.com Once unlock it,you will be able to use your favorite prepaid sim card when you need.