Solo joins a long list of providers including Visa, Visa Electron, Maestro, American Express, Master Card or Diners Card of which you can use to get Habbo Credits.
To get more information on how you can get Habbo Credits (to get things like Furni, Pixel Car effects, web groups or Habbo Home stickers) click here. You can use debit cards, credit cards, pre-paid cards (Wallie, Ukash, paysafe), your home phone, your mobile phone or even get a regular subscription with Pay Day Plus! Blimey.
Cheers.