Taken from the Finnish Habbo fansite Fusion:

Users can no longer obtain coins with Habbo [prepaid cards]. Fuse, which develops Habbo, has removed the [prepaid cards] from its purchase list, and new batches of [prepaid cards] will thus most likely no longer be delivered to retailers.
Launched in late 2004, Habbo [prepaid cards] have been an important channel for acquiring coins for more than a decade. The [prepaid cards] were generally sold for five and ten euros, with 30 euros for 30 Habbo coins and 10 euros for 66 Habbo coins.
The main points of sale for Habbo [prepaid cards] were R-kiosks and Tiimarit. Rare [prepaid cards] could be purchased, for example, from Silja Line's ship's youth facilities and Posti's offices. [prepaid cards] with different patterns were sold at each point of sale.
The reason for withdrawing [prepaid cards] from sales is probably partly the proliferation of standardized prepaid cards. For example, the paysafecard, which is favored by young people, can now also be used to pay at Habbo, so that there may no longer be any financial justification for selling a separate Habbo banknote.
The availability of Habbo [prepaid cards] varied in the end times, and the service was not developed to meet changing needs. In practice, the [prepaid cards] have been pitted for a long time, but removal from the list of accepted buying methods hits the last pound in the coffin of Habbo [prepaid cards].
As far as I am aware, this is the last country in which Habbo pre-paid cards were available and thus looks like it's the end of an era for Habbo, with tangible shop-bought prepaid services now replaced with online altrernatives such as PC Game Supply or PaySafeCard.

Does anyone on Habbox Forum live in Finland and know of the shops or kiosks mentioned? Any pictures of the last prepaid cards would certainly be interesting to see.