In my kitchen I would like to change my window into a bay window to make my kitchen look bigger, because it is so small. Would that be a project I can do on my own or is it best to hire someone, and if so how much does it cost

 

If its a standard size kitchen window above the sink, somewhere around 36w x 32H, you could get a garden window for around $600. Install would probably run $400 or so...thats just a guess, a lot depends on the type of siding, wall, trim, your location..etc etc.

You said bay window, but I'm presuming you mean abaove the sink. If its really windows in an eat-in kitchen or similar, that are much bigger...it could get very expensive...$2000-3000 wouldn't be out of line. Its all in the details...which we don't have.

Best thing is to call several reputable companies and get estimates.