I use the Oster Golden A5, which is still going strong after 18 years of use on my 2 Schnauzers, and for the last 5 years on my Yorkie & 3 Morkies.
It is great for the style of haircuts I do, which is shaved back, with longer (scissor cut) hair on legs and head (modified Schnauzer cut, or the "Joey" as we call it on YT).
There are attachment combs for different lengths, though I don't use them.
I also liked the cordless version of Oster A5 except when battery ran out and eventually it wouldn't charge. A replacement battery was $50 so I opted out.
There are so many nice alternatives these days, Andis and Wahl. People who are afraid of electric clippers may do ok with the Scaredy Cut scissor trimmer
Amazon.com: Scaredy Cut Pet Grooming Kit: Pet... .
Best scissors by far for around eyes, paw pads, and small areas:
Amazon.com: TINY TRIM ball tipped small pet...
One of the other important things to consider eventually is a grooming table with adjustable arm. Pups will learn to stand still and behave much better with one of these than if you do them on the kitchen counter or table (as I used to).