I'm looking at having a french drain installed and have been quoted $40/LF. Seems high to me for the St. Louis area. Is that reasonable? It is a relatively flat yard with few impediments. I need about 150' ran. One contractor stated french drains arent' good for missouri clay soils and suggested a swale or dry creek bed. However, this will be in an area that we walk and kids play so I don't really want a low spot or uneven surface. I feel like he was trying sell me on the swale because its easier to install. I was quoted $30/LF for the swale.

ol' dad

the type of remedy really depends on the situation...in clay soil either a french drain or a swale is just going to get rid of water that flows to it on the surface, jmo.

Need more info: depth of trench, stone size, fabric, topsoil and seed on top of trench.

as far as pricing 3-4 estimates should get you that info.

Rent an excavator and do it yourself. Should be under 500/day or 1500/week for a mini.

It would be hard to give you a idea on pricing without knowing how deep or how wide.
All mine on a property that I had were 3’ deep x3’ wide. Using that as a base every 3 feet is a cubic yard.
Drain rock should be available in 1 1/2 on down in size. I prefer the larger stone because of more water flow.
Then you will want to cover the drain rock with 4 to 6” of crushed clear. Some people will put a layer of weed fabric in between.

I guessing his quote was not that deep or wide. It it was that is a cheap.
I rent my mini out for 250 per day plus deliver and the dump trailer for 75 per day. Discounted rates for a week.
Then you will need to get rid of the soil and truck in material.