Yes of course. You can contribute as many
times as you like and submit as many website links as you like.
Here's two examples ~
1 - If you contribute in one transaction say 300 pennies, this
would mean 3 pennies will go towards the One Billion
Pennies pot, but only one website link will be added to the project.
2 - Or, you could contribute 100 pennies via 3 separate transactions,
then 3 pennies will still go towards the One Billion
Pennies pot, plus you will have the option to submit three separate
website links. This option would be recommended.