Depends if you’re concerned about him falling off etc, I went for a tower as they are safer (But that was for her 1st birthday)
We use a £4 stool from Asda for hand washing. I’d get a tower if you’re gonna have him up there for longer periods
We got this one and I'm really impressed with the quality and sturdiness for the price: https://amzn.eu/d/1wBP5iF We use it daily. My 2 year old loves pulling stems off tomatoes, putting toppings on pizzas, whisking/mixing, cutting green tops off strawberries and eating them on the spot. He loves to do these things "by nySELF!" Just make sure you have somewhere easy to stick it when you need it out of the way.
We brought a kids step from home bargins
We have a cheap folding stool to wash hands and a toddler tower that folds into a table with a bench. If you want one to help in the kitchen I’d go with a toddler tower and maybe get a separate folding one for sinks to wash hands, ours was just £5 from Aldi.