The $50 unit will last long enough for you to decide if you really like it. If you do, when it quits you can buy another or a better one.

Ultrasonics are good but do have some issues.
As example they don't do much for copper or leading of bores and whether they remove hard carbon fouling is mostly a matter of what solvent you use.
For carbon, you may be better off buying a big jar of Slip 2000 Carbon Killer. A 15 minute soak and some light brushing will usually pretty well remove the carbon from an AR bolt and carrier.
This is usually faster then filling the ultrasonic and having to empty it after.

Ultrasonics will remove ALL lubricant, including from tiny crevices and holes nothing else reaches. This does a nice deep clean, but you have to rinse and dry and then make very sure you get some lube into those areas again.

What solvent to use has to be carefully considered.
Any solvent that will damage something will do so faster in the unit. As example, many of the strong de-greasers like Simply Green and Greased Lightning will seriously damage aluminum and will do so faster in the unit.
Get careless and you can really ruin a gun or part.
Some solvents will damage some gun finishes, like the paint type coatings.
Choose the right solvent and you can clean plastic guns like Glock's.

To clean small parts like trigger parts you can use something like lacquer thinner by putting an inch or so of water in the tank, putting the solvent in a glass, plastic, or metal cup and standing the cup in the water. The ultrasonic waves transmit through the water, through the cup, and into the solvent.
As always, be very careful of using flammable solvents in the tank. If you're careful you can use ordinary cheap paint thinner as a solvent.

NEVER turn the tank on without a liquid in it. The tank will burn out very quickly if you do.

It's best to use a basket or wires to suspend the parts in the tank. It works better if you keep things off the bottom.

KEEP YOUR FINGERS OUT OF THE TANK. Ultrasonics don't play well with bone marrow. This doesn't happen immediately so you may feel it safe to reach into the tank while it's running. Doesn't hurt, but does damage.

A great cleaner solution is Cylinder & Slide Shops "Dunk-it". This is a bucket of a cleaner and lubricant mix.
You can just soak the gun in the bucket, or you can use it for the tank solvent.
It cleans the gun and leaves a thin coat of lubricant on all surfaces. This eliminates having to rinse and dry, then lube.
I'd still use a thicker lube on key areas.

If you use a water based cleaner, you can rinse by just dropping things in a sink of hot water. No ultrasonic rinse is really needed. I don't recommend most types of lubes in the tank as a lubrication cycle. Most lubes are too thick and the waves won't transmit through. Also, you have a gun dripping with lube that you can't get off easily.

To dry parts use a hair dryer to warm them. NO heat gun or torch. That's too hot.
Again, watch the sparks if you're using a flammable solvent.

For best results, let the tank run for a while until the solution heats up. Some better tanks have a built in heater.
Watch that plastic parts don't get too hot.

Note that painted on markings and sight marks will be removed. Some solvents will do so instantly, some will take a few times in the tank. Buy small bottles of Testor's model paint to replace the marks and sight markings.

Choose your solvent carefully and you can clean eyeglasses, watch bands (NOT the watch case, they'll leak), jewelery, elector razor heads, paint brushes, etc, etc.

Good information

I also picked up the large Harbor Freight model for 60 bucks but have yet to use it. Got it on sale and used a 20% off coupon . I heard that using Simple Green is as effective as the Hornady and Lyman cleaners while being a hell of a lot cheaper for 5x the amount.