Probably the simplest and cheapest, pre-assembled full function computer you could get is the Stratlogger. However, PerfectFlite hasn't had any in stock for over a year now, so that is maybe a future option.
A MissileWorks RRC3 is probably the next best thing in terms of price and functionality.
Once you get comfortable with electronics, just go with Eggtimer. I was intimidated at first by having to solder them myself - I definitely dorked up my first Quantum and Quark, but now I pretty much get them right on the first try 90% of the time (60% of the time, it works everytime?). I have probably built 50 Eggtimer components now and wouldn't go back.