You can get a printed copy of the 1897 Sear’s catalog on Amazon for less than $20. It’s over 700 pages, so it’ll have almost anything your players might want to buy, and it’s just a fun book to own in general.
This is a site that I've mostly used for D&D but they do have some western themed selections now, and other stuff that would work. Plus it's free, although they have a patreon page for anyone who wants to donate a bit, and you get other variants.
I used it for my first Deadlands game and there's a number of options that work really well in the western section. There's also a number of just audio effects on the pad, not much that works well for Deadlands but it's an option.
Tabletop Audio - Ambiences and Music for Tabletop Role Playing Games
I found these on Amazon (UK Site) which are both Western and Occult themed:
Direct from site if you don't want to Amazon it:
I highly recommend Comin' Round the Mountain, the sample adventure in the back of the original Marshal's Handbook. It is honestly one of the best sample adventures that I've ever seen.
It does a fantastic job showing how all the key elements of the game bind together (Diverse NPCs, Train Robbers, Secret Government Agencies, Horror Set-up, and Monsters). It also shows how to do the pacing/transition between Western and Horror (something so important to deadlands).
There's already a document for converting it into SWADE. The original Marshal's handbook can be bought here, but isn't very hard to 'acquire' elsewhere.
http://smile.amazon.com/Dead-Mans-Hand-Anthology-Weird-ebook/dp/B00GVZJV80/ref=sr_1_1
Great anthology, you can find all sorts of authors & series from it. The audible audiobook is great too.
Edit:Changed to Amazon smile link.