I have never understood paying the prices for the specialty tubs. A decent used regular tub, mounted on a frame so it's raised up to a comfortable working height has always worked superbly with me. Right now, we have shower pans mounted in raised frames. It's not only cheaper but it's WAY more comfortable in my opinion than any of the specialty tubs which tend to be too low to be comfortable to do any but the largest dogs.
I'm not much for needing fancy best top line to do a good job. I use double-speed andis clippers, the shop does have clippervacs that I use occasionally and they can be efficient and useful. Stainless steel comb sets(to use on the clippers, not like the brush and combs) are well worth the money instead of buying a cheap plastic set. HUGE difference.
A TABLE is one of the best investments in my opinion. Get a table that lowers as low as possible(usually a scissor lift style, not the round single tree) and electric OR hydraulic. We have hydraulics, no cords, no shorts, no switches to fiddle with. I groomed for many years with a standard table, no hydraulics, no up and down, just a table. It worked fine. But having the hydraulic table really makes a difference. A good stool is also important.
You don't always need to spend a ton of money to get good usable equipment. More expensice doesn't automatically mean it will work better.
And get two of everything, and 4 of each blade size you need. When a dryer goes poof, and you've got ten dogs to do, you can either lose the entire day's income, make ten clients annoyed, increase your stress levels.... or you can pull out your second dryer and go on with your day, making arrangements to get the broken dryer fixed in the meantime.
But most important in this job is the groomer. Without a good trained experienced groomer, it doesn't matter if you've spent a million dollars on the equipment.