The Mandolin is an amazing little instrument and there are two types.
Flat back which is the folk instrument, and bowl back, which is more of an Italian style.
Not too expensive to buy and easy to transport the mandolin is a lot of fun. It can be as easy or as difficult to play as you wish.
The neck is quite slim so if you have large thick fingers this instrument may not be for you. However, with the sound of Maggie May by Rod Stewart going through your head, it is hard to resist its charm.
If you already play guitar this instrument should be straightforward to learn, howvwer the strings are tuned like a violin (see below).
Low sound to high: string 4=G, 3=D, 2=A, 1=E in pairs.