rbrown pretty much covered it all. Here are a few links that might help too:
Making homemade stones:
http://www.tc.umn.edu/~keen0018/makeastone.htm
Purchase inexpensive, high quality logs and other equipment. (I own one of his 6ft logs myself)
http://www.tc.umn.edu/~keen0018/makeastone.htm
For farmers walks ideas, do a search on the boards here for them. Several strongman competitors have posted pics of their homemade creations here.
rbrown is right. Tires are free. I have two of them, and paid nothing. In fact, Les Schwab had one of them delivered to the store closest for me to pick up. Still no cost.
I have also made my duck walk and farmers myself from Lowes without welding. (I don't know how to weld, and didn't want to pay a welder at the time.) Here's a link that has several pics of some of my stuff I made at home:
http://www.joker47.com/Pics/Home Gym/
I also do a 4 day split, modifed WSB workout:
Monday - ME Upper
Tuesday - DE Lower
Wednesday - Tire practice/GPP -or- off
Thursday - DE Upper
Friday - ME Lower and Events
Sat/Sun - Off
Lifts vary, but the format stays the same. ME Lower and Events are 1-3 gym lifts, and 2-3 events. All OHP events are trained on Upper days as part of the workout.
Hope this helps some. I'm sure B-Fold could add more, too.