Since San Marino is part of the Euro Currency Zone it also mints own coins. The San Marino coins in particulary are very seldom to be found and most of the times they have to be purchased in souvenir shops. If you are a coin collector make sure you negotiate the price - since on my visit the price varied quiet a bit!!
To receive a stamp of San Marino in your passport one has to visit the tourist information office. After they have received the fee of EUR 2.50 one can obtain a tourist visa. There are no border controls since the country is completley surrounded by Italy.