Users will input a sequence of digits and you will find the smallest prime that contains that string in base 10.
input -> output "10" -> 101 "03" -> 103 "222" -> 2221 "98765" -> 987659
Shortest code in bytes wins. I do know that some languages (mathematica, sage, pari-gp...) come with built-in functions related to primes. -50 bytes if your program doesn't rely on such functions. Don't try to cheat on this please, if your language already has a huge advantage don't claim the bonus.
According to a few comments below, the smallest prime that contains "03" is 3. Does this really make a difference? The only thing I can think of is that maybe numbers are easier to handle than strings.
In cases like "03" the preferred output would be 103. However, I don't consider it to be the fundamental part of your program, so you're free to ignore any leading zero if it grants you a lower byte count.