The cost of the trip in regular bus, trolleybus or tram is 0.5 grivna and you should pay for your ticket in cash to a conductor on board. They can be overcrowded especially in "rush hours" because a lot of people (older people, etc.) travel for free. Also there are vans or minibuses, which are called "marshrutniye taksi", they have numbers and route written. They are much more comfortable and you always have a seat. If you see an approaching minibus just wave it down like a taxi. You will be charged 0.6 - 1 grivna when you board a van, then just tell the drived, where you want him to stop and drop you off.