Get the simplest, cheapest, old style j tube snorkel you can find. Don't let a shop try and talk you into a dry snorkel. I sell a simple j tube that I now recommend to all my students and even have kids in my YMCA and Girl Scout Snorkeling Skin Diving Programs using. Price $15.00.
Mask is all about fit. A $100 mask is junk if it doesn't fit and a $25.00 one is priceless if it does.
Boots depend on location but something in the 5 mil range is a good for most with a decent sole.
Fins - I recommend to my students who are only doing recreational dives a fin that costs under 50.00. Some other brands sell the same fin for upwards of 80.00.
I don't have any masks over $50.00 in stock and most are much less than that and fit a wide range of people. And I can get about 9 different styles in the one line. I also can get Apollo masks that run upwards of 250.00 for this one that is great for those who it will fit and need this particular mask and all the options it offers
Apollo Sports: Dive Gear: Masks: Bio Metal Pro to this one that retails for 79.00
Apollo Sports: Dive Gear: Frameless Mask
In short you can start out with as little as 125.00 for good dive quality Mask, Snorkel, Boots, and Fins up to several hundreds (like 650-700). It's all about what you need, want, your interests, and your wallet.