I see this question posted many times in the forums...
Are you new to detecting? Do you want a beginner machine and are on a budget? Do you want a cheap detector? Do you want enough to just get started?
The first thing you need to know is what kind of detecting you are doing. You also need to know your budget and if you really like the sport or not.
Why do you need to know the type of detecting you are doing? Because if you are trying to scuba with your machine you need a much different machine than if you are looking for gold in the desert. So what kind of detecting are you doing? If you are looking for a waterproof machine, you are going to need to spend at least $500+ to over 1000+ for the machine you need. If you are going to do beach hunting only and want to detect the wetsand, then its the same thing - you are going to spend a minimum of $500 and maybe need to spend much more. Now if you are just doing basic metal detecting, like parks, dry sand beach, etc. then you can get away with spending under $100.
So what is your budget? And do you like the sport?
Assuming you are an absolute beginner and are not sure if you are going to like metal detecting in a year from now and dont have unlimited income, I encourage you to spend as little as possible on a decent beginner machine.
My choice for a beginner machine is a bounty hunter tracker IV because you can find them for $60-$100 new. Other good beginner machines are made by each company like the fisher F2 and Garret Ace series. However, each of these machines more or less has the same depth but is much more $$$. What differs is features. However, I think most of these features are not worth the money, especially for a beginner. What I would like to see a beginner do is learn to use their ears. I don't want you to learn to rely on technology telling you what a target is because there are instances where that technology can be wrong. Learn to use your ears. The bounty hunter tracker IV is a great beginner machine that can accomplish this. And when you are ready to upgrade machines (and you will when you get into the sport) you will be ready to buy a good mid-high level detector which will run $500-$1000+ like the Garrett AT Pro, Minelab CTX, etc
So what is so great about this machine I recommend? I see 3 advantages to getting this over other machines. 1) Its cheap, like the cheapest detector you can get, so if you decide you don't like MD or you want to upgrade you didn't break the bank at all so your loss is minimal 2) When you do upgrade you can keep it as a backup machine or for friends who want to try metal detecting (and trust me your friends will want to try it) and 3) It will force you to learn to use your ears and not technology that tries to tell you what the target is.