Hey its close to city center and very easy to get there. We had hired a taxi for the full day which took us to all interesting places and turned out very reasonable. There are scooter and cycle taxis too which may perhaps be cheaper if you are travelling alone. There are no entry fees and no guides.. Its just a market.. You need to bargain a little but the prices are very reasonable for all African arts and crafts and fabric.. Its a market for local people where everything including fruits, vegetables, clothes, shoes... is sold... There are lots of tailors too who stitch a dress or a shirt in 24 hours at a reasonable price.. Vast choice for African fabric..

As a foreigner and specially if you cannot speak local language I would advice that u take someone with you who can manage the crowd of porters who (with good intentions) will surround you, all wants to be hired to carry your stuff. It can be uncomfortable experience for those who experience it for the first time. You can ask the driver or request the hotel to find you a guide. Normal people are very friendly and willing to help.

I have only used RWF and would endorse the earlier comments about not flashing the cash. Keep your money in separate small amounts so you only have to take out some at a time.

Yes to both questions, however you'd get a better price if you pay in the local currency. Have fun!