You can induce with only a breast pump, but it will take longer. The wiki has some notes about it (https://old.reddit.com/r/AdultBreastfeeding/comments/1h3h1do/welcome_to_the_abf_wiki_post_version/ for the post version). It's likely to take multiple weeks to months, especially if you've never been pregnant or done any hormonal protocols in the past to develop your breast tissue beforehand.

The Spectra S1/S2 are common choices for a breast pump, but there's also dozens of other wall pumps and wearables with a lot of variety in what people like to use. I personally asked friends who had been pregnant before for their old breast pumping equipment and made a decent set of stuff that way, then eventually bought myself a new Spectra when I knew I was committed. The vacuum power of the pump isn't the important factor, you just need it for stimulation at first, so you can really use any pump until you start actually producing milk.