There's tons of places you can find raincoats like that for pretty reasonable prices, but the trick is the timing. Earlier this year places were killing themselves to get rid of trenchcoats. There was a fantastic brooks brothers city trench on sale for like $120 back in like early spring. J. Crew/LL Bean/Land's End also have reasonable classic trench coats that look good.
related: I don't have a pinterest, but if I did, this would be on there: