I'm having the same issue. I expanded my barn early on thinking that I'd need the space but once I hit level 10 or so drops became rare. I can't get pick axes, shovels, or axes to save my soul. I wanted to expand to a junk pile but I can't even get the permits I need. I understand that higher levels need a slower drop rate or the game ends too soon but level 10 is far too soon to do this. I'm stuck and since the game was just released there is little to be found in the newspaper because everyone needs their extras and can't sell them off. It would be nice if there was a Daily Deal in the newspaper or something that gave parts for low gem prices or high coin prices. It's a fun game but there is some frustration with this.
However, I did find out that if you tap on a butterfly on your farm you can get coins. I hear parts could drop but that hasn't happened for me yet.
This game is slow it's all about luck
I've gotten hammers & a screw from removing the ugly shrubs. I was lucky to find someone had a deed (I think that's what it was) for sale at the newsstand. I snatched it up right away. Don't think they knew they would become rare soon or maybe they were quitting already.
I've actually sold about 2 old maps. I got more old maps than expansion deeds or the other map-y things. Not very balanced...
Don't sell them, you will need them later when expansion require 6, 7, 8, or more of each. If I had 25 old maps, I might sell one, but not less than that.
I don't have any shovels or saws now anymore either. So that's another rare item they want you to buy gems for. Not going there...never have...never will.