There are many charities that are run by sports organisations or with the help of sportsmen. These often have signed memorabilia to sell for the purpose of raising funds. It is a good idea to check with these charities from time to time and see what they have to offer.
Many large sports stores have specific sections where signed memorabilia is available. They have a fixed price on these products and generally have a decent variety available. In order to get those that you like, it is a good idea to visit more than one store and see what options are available.
There are various online shops that specialise in sports memorabilia. These websites have signed merchandise of all kinds and from all sports. They generally have hundreds of pieces at any point in time and one can certainly get what they like from these online stores. It is ideal that you make the purchase from a site that provides a certificate of authenticity which adds to the value of the product.
Online Auction Sites
Websites such as ebay and amazon generally have some different kinds of memorabilia. One can find sports memorabilia without much trouble and can choose from a fairly decent collection. These are sold by enthusiasts, fund raisers as well as professional sellers. Some of the rare items from yesteryear can also be found on these auction sites. There is a chance of a better price from these sites as well.
There are auctions taking place all the time so keep an eye on auctions related to sports. These will carry memorabilia and you can bid on the items that you like.
Teams themselves every now and again release memorabilia signed by their contracted players. There are various purposes including charity and fundraising. It is a good idea to get these if you find some of your liking as nothing is more authentic than these items.