Databasing

Sound Ideas and Hollywood Edge both provide free databases of their and other manufacturers sound effects. You can amalgamate the 2 companies collections and add your own effects to create a definitive database of sound effects.

Music resources

Apple's iTunes Music Store, AmazonMP3, LastFM, Spotify, Emusic & other services offer a great way of experimenting with various music ideas until you settle on something. The Amazon websites provide access to a wide range of music. Using Google will let you find obscure music appreciation sites and mail order specialists. Your local music library is a good place to look for older & deleted recordings- the Barbican Library in London is particularly good and offers a listen-before-you-loan service. Musical instrument shops often have a larger and more diverse selection of classical, folk, easy listening and music from the early 20th century than most mainstream record shops.

Record your own Sound Effects

There are lots of websites dedicated to this art, and a lot can be learned from cinema foley artists.

CD SFX Libraries

Boxsets of SFX CD's such as the Sound Ideas 6000 series (which has 40 CD's in the starter pack, and a further 70 CD's to add on) are expensive but once shows start turning over prove the cheapest option. The manufacturer's websites often sell them at reduced prices, particularly www.soundideas.com which has different special offers on a regular basis.

Online SFX Libraries

These are expensive to use regularly but are very useful for those elusive sound effects.

www.sounddogs.com

Individual SFX CD's from Record Shops

They're tempting to buy, but are often low quality and are rarely provided copyright free. Unless you actually database all the tracks they are a nightmare to use.