options for redirecting users based on user input

I am looking for a good solution to redirect users the come to my site based on a selection they will make prior to proceeding into the site.

The selection would be something like “choose the currency you wish to shop in” and the options would send the user to the specific site built around that currency.

I was considering creating a popup with the redirects built in and then thought perhaps popups may not be the best solution since a user can turn off popups. I also considered making the selection option the main index page but I didn’t think that would be good for the SEO.

I’ve also considered Geolify as an option but thought I would check for an option that would require user input rather than just redirecting the user based on their IP.

thanks for looking,