If I were you I would work backwards: What kind of sound are you trying to get? The cheapest way to go electric is to add a pickup (or two) to one of your acoustic mandos. If you add something like an old dearmond pickup, and put on steel strings, you get basically the sound of an electric guitar, without the wood of the mando adding anything. This type of pickup, just like most electric guitar pickups only senses the vibration of the strings. Other pickups like a contact pickup attach to the wood of you instrument and give you more of an acoustic sound. You could get your feet wet without buying a new emando for something like maybe $200. A 15 Watt practice amp goes for $90 on sale, and a pickup and cord shouldn't cost more than $110. I have a Crate 15 W amp that has a bunch of onboard effects, like chorus and delay and reverb, which is nice a light, but gets pretty loud. Not a bad starter amp.
If you are going to go for a new emando, I would get an 8-string, because you can always take 4 of the strings off and play it like a 4-string.
Electric solid body instruments are a LOT easier to make than acoustic instruments, so you could probably get a cheapo emando for $100 if you really wante to go low end. Look on Ebay. Having played my share of cheapo emandos, there really is a quality difference as you move up in class, but if you're not sure, I'd start with a cheapo one.
Forget with the cowbell, already...