Looking for first synthetic

I have been using an old badger brush for many years and it has served me well. I am looking for a synthetic for a whole lot of reasons. They appeared to have improved over the last 10 years. 

Looking for advice in what to look for as I reach out into a new era.

I went all synthetic in 2017. I have tried a bunch. My favorite since 2018 is the AP Shave Co SynBad.

Philosophically, desperately want to ditch badger hair as it a nonsustainable, cruelty derived product.

Unfortunately, despite having tried about every significant synthetic knot available, NONE have proven satisfactory. 

Realize, it offencive to continue supporting the badger culling industry but so far “there is no alternative” to quote another person of great moral failure and blind disregard to widespread suffering.

What's your budget / comfort zone for spending?

In the $15-30 range, it's hard to beat a Yaqi.

ApShaveCo, as MaineYooper mentioned is great in the $30-60 range, maybe?

You can also get some custom wood or resin handles from many on ebay such as Wildwest and CaYeun. Those will be a bit more, like $50-80.

So many good choices out there, it should be easy to find a great synth brush at a low price.

Your choices probably depend on how much backbone do you like in a brush then softness and size.
Edit: Another thought I had is whether you face lather or bowl.

About $30-$60 in that ball park

If you're looking for an off-the-shelf, but nice synthetic, there are quite a few great vendors out there. Which knot depends a lot on your preferences, but I've only tried a couple that I didn't enjoy, and that's because they had a bit too much backbone for my tastes. Here are my favorite synthetic brush vendors.

AP Shave Co
Phoenix Artisan Accoutrements
West Coast Shaving
Maggard Razors
Italian Barber
Shave Forge

I often use a synth. 
I know they’re very different than a badger brush, but they’re interesting.
I believe synth’s have evolved into some very enjoyable alternatives.

I’ve tried several synthetics and the selection from APShave work best for me with the 2BED being my go to knot. My experience with Yaqi has been disappointing as those knots just can’t compete with APShave.

Another vote for the AP SYN BAD.