Welcome to the world of paintball.
I highly recommend you look at getting a set of your own goggles first, before markers, suits, packs, etc. If you get second hand (and are unsure of the age) ensure you swap the lens for safety reasons. Your eyes cannot be replaced and its not worth skimping on a cheap set of lenses or goggles.
Once you have goggles, you can then get to a walk on site and see the different styles and makes of PB markers available - there is a lot. Most players will talk about their markers ('till the cows come home) and most will let you run a few rounds over the chrono/range.
Some sites (I know Holmbush nr crawley do ) will let you rent some site gear for a walk on day. Again, to see others play with differing setups will be invaluable. You'll get an idea about what style - mill sim, tourney, pump, etc. you might like.
Once you have visited a couple of walkons, to watch or play, then look to find your marker.
There are always lots of markers for sale here on PB and on Facebook and for most price ranges. Once you have an idea of the style of PB you want to play and the budget you have then you'll know what to search for.
As always ask questions here or on FB, there are always players willing to help.
NB I'm from Worthing and play at Holmbush (nr crawley), Campaign (nr Cobham), Weekend Warriors in Reading, Mayhem Essex, and a couple of North Kent sites where my old PB team originate from. All are walkons and friendly sites with a good following of players.
So again, welcome and have fun.
Regards,
Colin.