We recently completed the water line parallel to my driveway but when the water company installed the meter, they excavated and re-graded a large area on either side of my gate at the end of the drive. Much of the subsoil was red clay and now it's part of the surface again. It becomes a nasty slick mess every time it rains though it hardens like concrete in a few dry days.

Any tips on something cheap and fast I can throw down for a few weeks while I work out a better solution?

Wood chips? A liberal dust of Fast set concrete overnight? I don't care if it breaks up into gravel, that would be better than slick sticky wet clay.

People here in Charlotte like to use straw.

cover it completely with rye grass for now

The landfill uses mulch in bulk and spreads it when it rains. Not nearly as bad of a mess as it could be.

Pick up a trailer of mulch from Austin Wood Recycling. Single Grind is cheap

Scatter an inch or two of pea gravel on top of the clay, and after driving over it, and mashing it into the wet clay, it'll set up like concrete and last a long time.

Pet peeve of mine from construction days. It's not that much more work to separate the topsoil when excavating so you can put it back on top.

I would use 3/4" - 1" lateral line/septic tank rock. Cheaper than p gravel... and will give you some base that just won't push into the mud so easy.

Well, it's all about the economics of it, after all. I assumed a small amount (pickup load or less) would suffice and avoid involving a dump truck and spreading equipment. A shovel and maybe a wheelbarrow would suffice. Getting a load of base is more involved than may be necessary. The OP is a bright guy.

Well I read the "regraded a large area" and figured he would need more than a wheelbarrow full of something to make it not muddy. Actually the larger the rock the better when clay is involved imho. He could get 3/4 to 1" landscape rock at Lowes or HD in bags I guess? That would keep him from having to buy a dumbtruck full and getting a road grader and roller out there as you say.
My "leveling and hauling equipment" is usually ends up being my shovel, my p/u, my back and a heavy rake.

Availability and cost of material will be determinative. Either will do the job, but I'd actually prefer the material be compressed into the natural earth for a smoother surface. It should last for years under normal traffic.

One might actually apply the material in lifts rather than all at once for a better surface. The clay actually serves to bond the rock and stabilize it, much like asphalt, without the co$t.

Lime?

I had a similar problem and thought I would use pea gravel or something similar but ended up using concrete washout from our local concrete supplier (Lauren Concrete, Brenham). They told me I would not be sorry and they were right. Its very economical. I spread it out with a box blade. It is a parking area/driveway. Grass is growing through much of it a few years later.

If it is wet clay and has any depth at all, just about any rock smaller than 2" will compress into it if driven upon. I learned that lesson on my 1 mile clay road on our ranch in the ozarks. It was a bottomless money pit of clay. Ended up bitin the bullet.....dug all the clay out.....hauled in limestone 1" base.......then paved it. Problem solved. Albeit, a bank loan needed.

Just bought 5 dump truck loads of 1 inch limestone on Monday to add to our existing driveways around the shop/ barns/ ranch house. 4,300 for 5 loads which averaged around 12 tons. This is more than double what the same product cost just 5 years ago. Houston area so it's all railed in.

We have been pretty lucky at the place in the Ozarks. I just had a load (12 tons) delivered two weeks ago. They only went up $50.00 since 3 years ago....so i considered myself blessed.

Concrete washout is $23/yd.
A truck load 14 yds delivered in the Brenham area is about $350.

That's probably my long term solution. I have a pile of road bed but it contained much more powder/dust than I had hoped and I can't use it in a lot of places because it also becomes mud when soaked.