I have grown my company's Instagram account to 16K+ followers purely through organic growth (check tailormadeitineraries).
I have based my bid on 10 hours of work, however the more followers and engagement you want, the more hours that would be required.
This would be 'hands-on' work and not using bots or dubious follow/unfollow strategies that other so-called media managers use. My aim is to grow you a genuine, interactive following (not bots!). No guarantees can be made on how many followers you will generate (it will not be organic growth if anyone guarantees you a certain number of followers!), however, I would aim for between 1,000 and 2,000 new followers for my 10 hours of work.