Use the method shown below to take advantage of a glitch online to get a lot of money easily.

Step #1
First, head to Valentine's Ranch building.

Step #2
Shoot and skin the pigs or sheep one at a time.

Step #3
Take the animal carcass with you on your horse to the butcher in town (but steer clear of evildoers) and sell it for an easy $18+ two minutes later.

Step #4
Not only will you be able to do this with all the cattle on the ranch, during the die animals you killed there will have a chance to respawn.

Step #5
Keep repeating steps 1-4.