I do love the shield! But and still a ways out from CCW as I am not yet 21
It's easy to forget that states have so many different laws. For instance, New York has different kinds of ownership and carry permits. Next door in Vermont, all you need to own and carry is proof of age over sixteen. (While perfectly legal to own and carry, they still can't receive handguns from a FFL holder.)
Just like magazine restrictions in states like New York have boosted revolver sales, your situation has pointed you at a sweet range gun.
rcase1234, you said you've got about $500 to spend. Is the M66 your first handgun and will this purchase be your first semi-automatic? I ask because I've realized something about the guns I really love.
They stay with me. With proper care, they last practically forever and I can keep enjoying them again and again. Over a relatively short period, the gun becomes less expensive than the ammo you feed it. In the long run, a few hundred bucks is meaningless.
I share this because I love 4" K-frames (especially in .38 special) and I see the M66 as a lifelong partner that could give you a lifetime of enjoyment. Keep this in the back of your mind as you look at semi-automatics.
If you really love a Sig and you know it when you hold it, don't let the budget cap stop you. The price difference might mean waiting a little while, skipping a few luxuries for now, and squirreling away a little more than usual; but it will mean having the gun you love with you.