Toyota Repair: toyota yaris, toyota yaris, rough idea

Question
My toyota yaris 1999 semi auto ( mileage about 100 000) its gears get locked and then I have difficulty getting it into gear.
After it runs for a while it becomes smooth with relatively little gear problem.
it is worse in the morning or if it has been sitting for  a while.
A light flahes when this happens.
I took it to the mechanic who looked at it and said they were not qualified, but after that it worked like a dream for a month.
My gut feeling it is the clutch.

Please give me a rough idea what it could be and how much I am looking at.

Answer
I believe the clutch is hydraulically operated on this model so I would recommend checking for a clutch hydraulic leak at either the master cylinder or the release cylinder on the transmission. The mechanic who looked at it may have just added some fluid to it which helped for a while.