2004 Kia Sedona Leaking oil Making strange noise

I noticed last week that my 04 kia sedona is leaking oil, not a lot but it's still leaking, I checked the oil it isn't showing that it's low and it also is making a loud rattling sound when I start it occasionally, not every time but I'd say 1/2 the time, once I drive it for a little bit the noise stops though, the sound has been going on a few months, today I also noticed when I put it in reverse it is kind of jumpy, not terribly but I can feel it with my foot on the brake, The car only has 71,000 miles has been maintenanced regularly and no oil/check engine lights are on it just past all emissions and safety inspections last month, I need to take it in somewhere and have it looked at but I do not want to be taken advantage of at a mechanic and I would like to know an idea of what is going on and estimate of what it is going to cost! I only use this vehicle to drive my kids back and forth to school and just around town so mainly worried about safety and getting the issues resolved. Thank you!