Is there a cheap AR10 vise block on the market. I don’t foresee myself building anymore of these

I’ll shoot you a PM, you can borrow my Midwest reaction rod.  

Flat-top?  Can't get much cheaper than this and it just plain works:

Small gunsmith supply company, Squirrel Daddy. Last I looked, ~$23 for the upper blocks shipped. ~$18 barrel blocks shipped. I've seen pictures of people using the upper blocks in a vise incorrectly. Basically it's a slightly better version of s4s4u's set-up. It can also be modified to work with AR15's (mill a second lug slot).

A flat top upper receiver can be held directly in a bench vise.  The receivers top rail goes against one vise jaw, and the bottom surface of the receiver is held against the other vise jaw.  Of course, use soft jaws (or pieces of 2x4 wood) which are large enough to spread the force over the complete rail / bottom surfaces of the upper receiver.  You're just using the vice jaws to stop the upper from rotating due to the wrench's torque; you don't need to apply much vice pressure to actually squeeze the upper.  It's the same concept as using a plastic clamshell in a vise, except the upper is rotated 90 degrees sideways along its axis.

Yeah just clamp it in a vise with wood, super simple and super cheap. As shown above with aluminum blocks, you can clamp the barrel too in blocks of wood. Google the term 'wood barrel vice block'. Just clamp the barrel against the grain, not with the grain of the wood or the wood can split.

I have made barrel blocks and built lots of 5.56 uppers. I member here was nice enough to let me barrow a 7.62 reaction rod. That is the best tool for the job. If I build another large frame AR, I will make a block

I've used a small synthetic cutting board cut in half. Both pieces go in the vice between the jaws and the action. I also use a reaction rod and it works well.

i found squirrel daddy 1 night searching the internets for gas block roll pin punches. ended up ordering $100 worth of tools. and that’s saying something because the prices are super low.

i have to recommend the Sq Daddy 3 piece punch set for gas block roll pins. i can both remove & install that roll pin in less that a minute with this setup.

also, the ar10 vice block they sell works well with the barrel extension torque rods secured in a drill press vise type of deal. i can loosen & torque big frame barrels, assemble/ disassemble big frame uppers on my living room floor with nothing else except a large crescent wrench on the barrel nuts & 1/2-inch ratchet on the torque bar

when i started out couple years ago i would spend so much time, energy & frustration using whatever automotive tools i had already laying around.

having the correct tools for the work makes the task so much easier & faster.

also, i’m not buying, ordering and waiting on misc items that were destroyed using whatever tool was handy, IE roll pins, barrel nuts, castle nuts, and so forth

i once used my pneumatic air hammer with the chisel attachment to bust loose big frame AR barrel nuts  

Appreciate the heads up on Squirrel Daddy. Just ordered some 308 tools.