Firstly; I would NOT get an acoustic (unamplified) guitar straight from go - the thicker strings and neck can discourage further study, the quality of most acoustics below $500 is rather inconsistent and any acoustic good or bad is highly sensitive to temperature and humidity.
An electric, on the other hand, is extremely low-maintenance and quality is relatively consistent even to the below-$100 range, not to mention more comfortable in the hands for longer intervals. The choices for body shape, color, hardware and pickups configurations are almost overwhelming. Shop for FEEL, then SOUND, then LOOKS.
But for just starting out, something from an established brand like Squier (Fender), Epiphone (Gibson) or Ibanez can be had from a music store chain in a "Starter Combo" (guitar, amp, and accessories) for under $300.
But if they really develop a serious interest in music, steer them toward bass guitar - they'll be virtually guaranteed a spot in any band they wish to join
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Let's go on out and take a moped ride, and all your friends will thing your brain is fried, but you can't live your life too dirty, 'cause in the the end you're born to go 30