If you have good content, the subscribers will come by themselves. A fast way to gain followers but for what you'll have to pay is http://igautolike.com . I heard a lot of people that use it when starting on Instagram. Most of all businesses and upcoming stars.
There is one rule for the development of such accounts. No need to be too serious and post exclusively on business topics. Cars are great but we are all ordinary people and we want entertainment the most. Try writing on abstract topics in your story. I like the theme of astrology and numerology. Tell us what ninety nine means. This information is available in open sources and does not require payment. People are interested.