You should never use a personal phone number for offers, you will get lots of spammy phone calls. There are a few options you can use other than your personal phone number.
Google Voice - Follow instructions for creating Google Voice numbers. You can make and receive calls with Google voice.
K7 - Follow instructions to create a phone number, for desktop, you can only receive voicemail via downloadable audio files in your email at these numbers.
Pinger/Text Free App - Download to your mobile device (tablets too) and register for a phone number in your area. You can make and receive phone calls and receive sms text messages from these numbers. Easy to get a fresh phone number by logging out and creating a new account. You have a limited number of minutes for each phone number.
From play store: https://play.google.com/store/apps/details?id=com.pinger.textfree.call&hl=en
**for compatibility issues use this link, be sure to allow installations from unknown sources:
Burner phones - these are real cell phones that can be purchased almost anywhere, usually no contract with pre-paid minutes.