Ibis Hotels are nice and "cheap " for Paris. Parking your car however can cost up to 70€ per night so be aware of this. ( no double entendre, i do mean the vehicle you may rent)
Ibis is the cheaper one, good tho, all comfort there for a reasonable price.
The other ones belonging to the Accor group are more expensive, F1 Hotel, Novotel etc.. a clean room ,bed and own bathroom is all you need, don't see the difference in why paying more for the same room.
For transport,buy yourself a 3 day ticket for the Metro system, easiers and cheapest,quickest way of getting around.
When you go to a cafe ( pub ), know it is cheaper to order wine then lemonade as they will charge you the same price for a small glass.
It is also cheaper to order at the bar then letting the waiter come outside to you, i remember them charging 0.70 cent more because they had to bring it outside to us.
Other then that, April/May is a great time to go, at least its not flooded with as many tourists as you would have in June and further onwards.
Enojoy it as its a lovely city to visit, and take your time doing so.