Does anyone have a recommendation for a tractor GPS for spraying pastures. I'm done with using a foam sprayer as the one I have is very unreliable. I know commercial GPS navigation is over $4000. Is there anything cheaper that you can recommend?

TeeJet is an affordable basic set up.
Trimble and Raven make some affordable ones as well. I found a company that sells refurbished Trimbles. I liked that as it was a larger screen and simple to use.
Go with the outside gps reciever upgrade. It will add accuracy.

The Manufacture and Age of your tractor have a big impact on what is the best option. Hard to give a specific recommendation with out knowing more details.

2025 Kubota M5-111. 105hp
Auto-steering isn't really necessary. I just want to see my lines. I have a 500 gallon tank which lasts for about 3 hours a time. Thanks.

That was the same with me. I didn't need auto steer. Just wanted to see where the fertilizer and herbicides went. Once you get it set up for your field and your equipment it is really nice!
Tractor age and type doesn't really matter for that application. It sure beats messing with the foam markers…..and it works with any spray or broadcast implement.

I used an app called "Tractor GPS" on my phone this year. It wasn't great because it lagged a little and didn't seem to have the option of "route up". Therefore, at times it was challenging to follow. Overall though, it was a ton better than not using anything. I'm assuming it was accurately tracking where I sprayed, but won't know until follow up to see the weed kill.

Trimble used to make an EZ guide 250 that was simple, inexpensive, and easy to use. Wish I hadn't sold mine. You can find them used on the internet. Other than that the Teejet Matrix 430 seems to have filled that space. Raven is another option.

Agree with ez guide 250 and buying used on Internet. I started with 250 and later added auto-steer. IF you're only running for an hour or two at a time, any light bar system will work well enough for you. If you are going to be out there for an 8 hour day, bite the bullet and get some sort of auto-steer.

Mine was this huge electric motor with a wheel, that turned the steering wheel. Ugly, but effective.

Lets you post on TexAgs while plowing

The Teejet 430 is intriguing. I would like to get a good review from someone.

I'm not going to be much help with just a guidance system as everything we run on our farm is true Trimble auto steer. Whatever you decide, I'd shop ebay or FB groups/market place. You can find used systems and save quite a bit.