We need to build a wireless bridge between two sites. Do we need to pay periodic cost to some vendor like we pay for private line for ex:- To block some frequescy to send our data
No, you can use any of the Cisco bridges because they use frequencies designated for public use. Once you've purchased the bridges, you are free to set them up anywhere you want at no additional cost.
Keep in mind that since these are public frequencies, everyone is using them so interference can be a major concern in some regions. You'll want to conduct a quick wireless survey using a spectrum analyzer to ensure that a particular frequency is clear.
The Cisco 1300 uses the 2.4GHz frequency range, which is far more crowded than the 5GHz frequency range. The Cisco 1400 uses the 5GHz range.
Let me know if you have any more questions.