New accordions will usually be supplied with a hard or rucksack type case. However, if you have an old accordion or you case has come to the end of its life there are many different styles you can purchase.  It may be advisable, if you can,  to bring along your instrument for a fitting.  
    

Accordion and Melodeon straps come in all shapes and sizes. It may be advisable to bring your instrument along for the straps to be fitted (at no extra cost). Prices start at £10.99 for a single leather melodon strap up to £54.99 for a pair of luxury padded 120 bass accordion straps.