Well ... A good place to begin might be the sponsors of this forum. Personally I will support my 'local dealer' by purchasing from him or her prior to going elsewhere. You might also consider going to a website that will give the the basics in education about the hobby of metal detecting.
MD'ing for Beginners It's okay to get the opinions of others, here on the forum, but that's exactly what you'll get ~ opinions (all be it some may be very good). The Ace 250 is one of those detectors that will bring varied opinions, as to its ability.
To be sure, everyone's opinion may be different regarding the ideal metal detector, for those 'New' to the hobby of metal detecting, but there are 5 that outshines the majority when it comes to value, quality, ability, reputation and warranty. It's my opinion the Minelab X-Terra 505, the Fisher F5, the Teknetics Gamma 6000, the Garrett Ace 250 and the White's Coinmaster Pro are the best of the starters in that they have better balance making it easier to swing for several hours without arm or shoulder fatigue. These detect deeper than their counter parts, within their price range, and have better ground balance, as well as bigger and brighter digital displays. Chose wisely. Chose Minelab, Fisher, Teknetics, or White's detectors. For those who prefer quality detectors without digital displays, Tesoro detectors, with a lifetime warranty, would be your best choice .
My thoughts for the day. Senior Seeker