A $30 camera slider, no way!
You better believe it.
Here is a way to build a simple. effective, and wildly inexpensive camera slider in about an hour. This slider is simple to build with basic tools and has a weight capacity of 11lbs!
Lets get to it!

Step 1: Tools

Drill and drill bits
Countersink bit
Vise or clamp
1/4 20 tap
Another smaller tap, I used 2.5mm
And a saw.

You can you hand drills and saws but if you can use a drill press you will find drilling the small bits a lot easier.

Step 2: Supplies

Here is your shopping list.

From IKEA
LEGITIM Chopping board $1.49
KVARTAL Glider and hook $2.00
KVARTAL Triple curtain rail $19.99
KVARTAL Ceiling fixture $2.50

You will also need 2 1/4 20 machine screws about 1/2 long plus a 1/4 or 3/8 machine screw to attach a tripod head or camera directly to the slider cart. Make sure these screws have a tapered as they need to be countersunk completely.

I used 8 3mm cap head screws that were 8mm long to attach the gliders to the cart. Whatever little screws you get for this you should also get a tap for that thread, you may be able to cut the thread with the screws them selves but a tap is only a couples of bucks and will work better.

Step 3: Assembling the Rail

We start with the KVARTAL Ceiling fixtures. First remove the set screw with the supplied allen key and disassemble. Now tap the hole with the 1/4 20 tap on the opposite side of the set screw, fortunately this hole is almost the perfect size for this tap. Now reassemble the fixture, remove a plastic end cap from the KVARTAL Triple curtain rail and slide the fixture on, tighten the set screw to secure it in place, repeat this for the other fixture. leave the plastic end cap off for now, this is how the cart goes on the rail.

Step 4: Building the Cart

This is the hardest part and does require some accurate measuring and drilling, it is simple but don't rush it.

It's time to cut the cutting board. I made my cart 3" x 4" but you may want to alter this to fit your needs.

First mark the center of the cart and the proper sized hole for what you are going to mount on it, I drilled a 1/4" hole. You will need to use a taper head screw to affix your camera or head and you must countersink the screw so that it doesn't touch the rail, if it does touch the rail you will have a bad time.Next we mark and drill the holes for the gliders.

Measure the distance between the slots of the track and mark that on the bottom of the cart, use the center hole you drilled as your center line location. This is the part that needs to be pretty much perfect, If one of the gliders is out of line it will drag too much and make the dolly hard to use, measure three times. After you are absolutely sure your holes are marked where they need to be go ahead and drill them. I chose 3m 8mm cap screws because they are small enough to fit in the holes we will drill in the gliders and I had a bunch of them. I drilled the appropriate sized holes for the screws then used a second drill bit to make the tops of the holes big enough for the caps to recess and sit flush, if you do this be careful not to drill too deep or you will ruin your hole.

Time to alter the gliders. You will need to cut off the little loops, try to cut them as flush as possible that way there will be less sanding to do. You will need to sand these so that they are flat on top, just wrap a piece of sandpaper around a scrap of wood and rub the glider on it, it doesn't take much so be careful so that you don't over sand it. Now drill a hole through them the appropriate size for the tap that you will use to affix them to the cart, tap these by hand and then screw them on. Don't tighten them up just yet, leave them a little loose. now see if it will fit onto the rail. If it goes on GREAT! Tighten the gliders down and try again, you may need to fiddle around with them a bit to get them all aligned but it should be quick.

3D printed quick release

One more step to go.

Step 5: Lets Give It Some Feet.

You can go ahead and mount this dolly on too a couple of tripods and have at but we have some material left over so lets make some feet.

Cut two more pieces about the same size as the cart, maybe a little bigger, out of whats left of the cutting board. Mark and drill 1/4 holes in the centers and countersink the bottoms, push a 1/4 20 tapered screw though and attach them to the fixtures on the bottom of the rail.

That's it! Time for some sliding!