65 meter wireless best option

I want to create a cheap "you've got mail notifier" that I can put in the mailbox. The problem is the mailbox is about 65 meters away from my house and there are 4 houses in-between. What wireless transmitter would you recommend? I was thinking of buying rf transmitters but from the reviews I read they barely work for 100 meters and that's under ideal conditions with clear line of sight.

reflections etc can be very disruptive for signals so you might start with relative cheap 434MHz stuff

e.g. check this one - SparkFun RF Transceiver Breakout - RFM22B-S2 (434 MHz) - WRL-10154 - SparkFun Electronics -
especially read the comments about a modtronic thingie

I've tried several tranceivers. The one with best range and the least trouble is the APC220.
It talks as your serial monitor.. Range 1000m+ with 17cm antennas
Select the variant with 433MHz

there is a company in the UK called solwise and they have links that can work up to 30KM
I have used there stuff its good.
there might be something of use there

not all wireless techniques are allowed in all countries…

cheap … 65 meters

How do you propose to power this?

I believe Bluetooth LE is good for this distance, and NRF24s with external antenna can be good for 1000m. Both are very frugal.