I have the largest one Harborfreight sells (2.5liter capacity). I bought it for around $55 or so, but everytime I see it now, the price has crept up (must be very popular). It is now on sale for $75.

In my view, ultrasonic cleaners are way overkill for cleaning bicycle chains. I use mine in cleaning my sunglasses, waterproof wristwatches, shaving blades etc.

And the HF one is good and useful to have around.