This year marks the 30th anniversary of our beloved MSX computer system. To celebrate this event, Konamito created some special T-shirts. In a limited edition, the T-shirts are available on Spanish and English. The price is € 12,- and the shirt can be bought at the 2013 Retromadrid event. If you're not able to come to Retromadrid, you can also have them shipped to you for a small postage fee.
To reserve your T-shirt, you can order one through the order form on Konamito's website. Reservations for this special price close on February 28th, after that date the price will be € 14,- + shipping.
Relevant link: MSX 30th anniversary t-shirts order form