How "recently"? The app being a charge is recent. Either your friend got in just before it was chargable, or she hasn't downloaded the app at all and is using the mobile version of the site.
The app was made pay-charge because it takes a lot of work to create and doesn't bring in any revenue by advertising.
If you've had it before you should be able to download it again on the same account. Eg if Apple, go to the itunes store and you should find a section where you can view previously downloaded apps and re-download this one. However, if you've switched from apple to android for example, on the new platform it doesn't know you ever had it and you won't be able to do that.
Deb, in New Zealand