I charge between $2-3K a day. But i have 20 years experience and worked for large clients and at big companies.

My best advice is the find an industry which have a lot of consultants working (so you know clients have the money) and then offer yourself as a consultant with a design, tecnical, financial etc approach. I.e be a niche player in a large industry and never grow bigger than 10 people and instead start charging for things that are scaleable and which clients can use even after they move on.