there are 2 options. but if you plan to add more camera stuff, then i will suggest you buy a dry cabinet
something like this from local shops or websites (do a search on it) >>>http://shashinki.com/shop/aipo-digital-series-ap68ex-cabinet-p-1510.html
then you do not have to monitor the humidity after you adjust it to 45RH%
small one costs abot $160- $200.
or you can get a dry box (link above) from camera shops (about $25) but you have to buy silica gel & change it when it turned pink (depneds on how often you open the box)