As I understand it, you should provide true, accurate information.

Some entry forms which require phone numbers have a note in parenthesis to say that the number will be used only to contact the winners and will not be shared with third parties, for example. You could check the rules to see if the phone number would be used for marketing purposes.

I have been contacted by phone a handful of times for wins, and I would not want to have missed those particular wins.

I have been contacted by phone only once for marketing, that I remember. It was from one company, but several times (I did not answer). If I had read the comments SA members posted under this particular sweeps, I would have seen that it was one known to call and annoy people, and I would not have entered. So, always try to read the comments before you enter. Our members are great and share info and warnings, both from their experience and from having read the rules.

For most sweeps, it is okay to give your phone number, and you will only be contacted if you win. Again, check the rules and comments.

You're welcome! 

I use a real number.

I use a prepaid cell phone for my contests.

90% of the time when that phone rings it is a WINNING call.

Either local contests or the larger online sweeps. "Sunny D is one example for me"

I also use it for texting.

And having the 2nd phone gives me a upper hand for radio contests.