I don't recommend doing it, but it is possible to deploy your application to a device without paying for a developer account on a jailbroken phone. This (can Jailbroken iphone used for development) question has a lot of info on how you would go about deploying your app. This (Install iOS Apps on device without developer program, iOS 5.1) question has great step-by-step instructions for what you want to do. Here's a sample of the instructions in the second link:
- Create self-signed certificate with name 'iPhone Developer'
- Turn 'Code Signing Identities' in Xcode project Build Settings back on - to use your self-signed certificate 'iPhone Developer'
- Change info.plist occurrences as stated
- Download ldid, make executable
- Create python script, stick it in /usr/bin, change python script references accordingly
- Change iPhoneCodeSign.xcspec to use ldid3.py
- Create tdmtanf file on device with touch over ssh
- Don't put -gta flags in 'Other Code Signing Flags'
Hope this helps!