Both factors (guitar and lessons) depend on two things.
If you're not too sure you're going to keep playing, or if your budget is tight, go with a cheap acoustic guitar.  Then, after a year or two, if you really like it, go either with a well-priced electric or a very good acoustic, depending on if you want to start electric or keep going acoustic.
As for lessons, ask yourself this.  Do you just want to have fun, play popular songs for friends or a band, or do you want to do that, but also know the theory behind all the chords (major, minor, seventh, ninth, augmented, diminished, etc...) and scales to eventually become a really accomplished player?  If it's the first one, you can just take one or two lessons to know the basic chords and one or two scales to jam.  You'll then be able to buy or download tabs and learn songs by yourself.  If its the second one, then take lessons regularly, you'll eventually become much better.
A tip: don't give up after a few weeks because you find it boring or too hard.  Eventually you'll never be able to stop playing, and you'll never be bored again.
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'I'm the master of low expectations.'
'I understand small business growth. I was one'
-Dubya!