Start as low as you can to see traffic. It will be different for every vertical. If that means $1, then it means $1. Google will tell you where to start more or less to start getting traffic in.
Google will also tell you if you are below the recommended daily budget and if you are losing clicks due to not assigning enough money. Start with enough of a budget to drive calls, but be still be able to scale up by daily budget, once your campaign is dialed in. When you're getting traffic, you'll stop raising bids and start optimizing your KWs that are getting traffic. We call it low hanging fruit. After that is done, you'll raise your bids on the below first page bids only (in training under part 7 optimization).