In Need Of Lots Of Tips!

The best all-around detector in that price range would be the ACE 250 (used). Lot's of them seem to be available from folks looking to upgrade. You could use it without accessories, but headphones and a decent digging tool will make your life easier. Headphones help pick up the very faint signals and will also allow you to discriminate trash from treasure once you get the hang of the machine. And concerning an instruction book ... they are all available on-line in .pdf format.

The best advice I could offer the newcomer would be to "hang in there." You will be digging a lot of trash before you find your first treasure (99 out of 100 times this is true). But those trash finds will help you learn your machine's characteristics. If you have some silver/gold pieces that you could experiment with, do it in a controlled environment. Note the tone and signal strength differences between silver and gold compared to other non-precious metals. After a bit of practice you'll be able to discern most trash from treasure based on the tone.

Good luck.

I am very happy with my recent purchase of a brand new
Bounty Hunter Tracker IV. Found the best price I could online
at Amazon.com. $90.00 shipped. I did a lot of research on it
and read very good reviews. Had it only a few weeks now and with
a find today of a 22" .925 silver necklace that weighed over 50 grams
along with all the coins found it has now paid for itself. Not bad for just a few weeks. Very light weight and easy to use and understand.
I bring along for digging a set of small gardening tools. A spade and a
3 pronged cultivator/weeder. I guess that is what they are called. The 3 pronger works well in loose dirt/mulch/mud etc. You can rake through the material with it and bring out your target to the surface. Start off small and shallow looking for coins/jewelery. Get used to the tones etc. and master your coil swing :)
Warning: You will get addicted to it once you find your first cent, dime, nickel, quarter, ring, necklace etc. Keep a set of spare batts.
in your vehicle also. Not sure what kind of shape your in (I'm Old:)
No not really, but you will be walking, bending, stooping etc. Also
depending where you live and especially now with the warmer weather watch out for ticks and poison ivy. I got both the other day. You do have to have patience and be persistent. I have never not found something decent on any outing. Not trying to push one make or model
but I think that the one I mentioned will foot your bill and you will be very happy with it. Try not to get too caught up with the diff. types of machines and learn how to use the one you decide on. It's the operator that finds the goods not the machine.

I had a look at big fredd's site on the main page and was wondering if a Ace 150 would be worth buying?

Is there such a thing as metal detector "ettiquette"... Like where NOT to be digging. I'm sure woods, and fields where old buildings used to be would be good places, but what about urban settings? Just a question...

Urban centers are a little tougher. But ?
Just rent a jackhammer and a compressor.
Wear an orange safety vest and a hardhat and your all set.
No one will even notice or care if you are tearing up the streets.
If anything, people will say well at least our tax dollars are being spent in a worthwhile manner. Oh, don't forget your safety glasses.
Maybe also get a police detail to watch traffic etc. for you.
I'm gonna hit the old "Combat Zone" in Boston one day this year.
Plenty of quarters around I'm sure.