There are a few modular builders in the Toms River area.Some are
Sica Industries Inc -Statewide Modular homes - Modern Homes Inc.-Prima Builders Inc.
As far as cost. They are a little more than site built homes. But the time saved by using modular homes can be worth it. The cost will vary due to site conditions and options purchased. The best thing is to have three contractors give you prices based on your needs. That way you can have an true idea of the cost.
1) Pilings required
2) Raised or on a slab
3) Local code
4) Fill around site if allowed
5) Check with insurance company now to get possible quote, and adjust 1-4
6) Make sure modular quote is for house that meets/exceeds Florida 150 mph code
7) Go visit modular factory - quality varies significantly