If you whant to get into rebuildables, you cant go wrong starting with an RSST. Fairly cheap, easy to find one and by far one of the easiest to set up. I might be slightly bias since it was my first, yet everything I have tried since has had some form of issue which the RSST has features built in to prevent - insulated wick hole, spring loaded wire capture, polypro
tank etc. For the money, you won't be unhappy. It is a little big and semi heavy and yes, it will leak if on it's side.
I have yet to find a "affordable<$100" device that does'nt have some leak issues when taking everywhere. I am hoping for the day that ecigs are as easy to use(hopefully easier), carry and as to find/ purchase as analogs are. We
are using a liquid inside a form of tank that has to have at least two holes in it to deliver the vapor. Yet there are many devices that do a good job in most cases. Wish there was something I could just throw in my bag/ pocket and drive from Az to Cali(altitude change) or walk outside in the Phoenix summer and not have to worry about leak issues. Happy hunting.