So I've been looking around to see what vst gate /expander ppl use to isolate there drum tracks stems. I kept running into old articles which didn't seem relevant. I saw one that was exclusive to pro tools which seemed awesome but haven't found an affordable alternative. What gate have you found that works for you. Thank you

You never go wrong with Fabfilter: https://www.fabfilter.com/products/pro-g-gate-expander-plug-in
 
Though my favorite gate is Polyverse's Gatekeeper: https://polyversemusic.com/products/gatekeeper/
But this one's more on the wild experimental side of things than a simple gate.

I was looking at the fab gate, does it ever go on sale? Thanks

If you have never purchased a FabFilter product, any existing  FabFilter customer (including me) can provide you a discount code.
 
FabFilter does have sales which spotlight individual plug-ins and bundles. Recent Black Friday sale was an additional 25% off individual plug-ins for existing customers and discounts for all their bundles. FabFilter started using resellers a year or so ago. They occasionally have better pricing often times better than the first buyer discount.
 
They also occasionally show up on the kvr marketplace.

Yeah Fabfilter Sales are rare, and typically on one thing at a time. I waited over a year to pick up Saturn, the same with Twin. But They do seem to becoming more frequent as I picked up ProR in December from a third party, and it's only about a year old.
 
Another cool thing to fabfilter, when you buy one, all the other items direct from them receive a discount.  This is particularly cool when they them selves run a special as it applies on top of the discount.
 
Otherwise Boz Gatey Watey has a trial option and good gate with some additional functionality.
https://www.bozdigitallab.com/product/gatey-watey/

If you are recording a real acoustic drum set with microphones, and want to isolate the toms, then the Sonitus gate included in Sonar is very good. It has separate high-pass and low-pass filters connected to the sidechain so you can "tune" it to the drum you want gated. This helps prevent false triggers. 
 
If you want a gate that is a little bit better than the Sonitus,  then get the "Unfiltered Audio G8" from Plugin Alliance.
Wait for it to go on sale for 19 dollars.
 
EDIT: The Sonitus is not a VST. It is Direct X. It will only work in Sonar and other DX hosts.
I still recommend the "Unfiltered Audio G8" for a good, low cost gate. It is VST.
 

Kamikaze
... 
Otherwise Boz Gatey Watey has a trial option and good gate with some additional functionality.
https://www.bozdigitallab.com/product/gatey-watey/

Thanks for the reminder about Gatey Watey. I snagged it for free when Boz were doing the "name this new VST" promotion, installed it...and promptly forgot about it.

In your OP you mention Stems. Stems implies there may be multiple tracks being sent to a stem. Any gate or expander is always going to have a more difficult time dealing with multiple sources on a stem. Treat the individual tracks before they are sent to a stem.
 
Also I see if you are running Studio One, the built in Expander does a fine job. You just have to spend a little time setting it up correctly.
 
If I see only a few tom hits on a given track I actually cut out all the time in between them and apply a short fade to the in and out on the event that is left.  No gate or expander is as clean as this.  This is actually pretty quick in  Studio One and easy to do. 

Can also get the excellent Reaper gate for free (ReaGate). Highly recommended. Comes included with a suite of other top end vst utilities. Don't got to love Reaper to love this offering.
 
https://www.reaper.fm/reaplugs/
 
John

Has anyone tried https://www.dmgaudio.com/products_expurgate.php . It looks promising.