Radarspotting

I'm new to this but crazy about planes.
I have some questions

1)  I've read about the SBS-3 and radarbox. And i found this website http://www.radarbox24.com/
Why should I buy a sbs-3 or radarbox if I can use that website? Can i do and see more if I own one of these 2 things?

2) On the website on the right there is this 'airport events'  like a widget.. Is this also avaible in the program itself?

Welcome.

If you're happy to just view plotted aircraft on a free website you have lots to choose from:

www.Flightradar24.com

www.Planefinder.net

www.radarvirtuel.com

www.radarbox24.com

Some of these websites have much more coverage than others and offer different features.  Since they're free I'd recommend you check them out for yourself and decide which you prefer. 

There are also mobile apps, notably from Flightradar24.com and Planefinder.net costing a few Euros. Flightradar24 also offers a Premium subscription option with enhanced website features, customised alerts and free use of all its available mobile apps.

If you want to do more than just "watch", you could buy your own Mode-S receiver to track aircraft in your local area, including non-positional aircraft.  Most receivers include software that you can customise and an aircraft database.  Suitable receivers include:

Kinetic's SBS-3

AirNav's RadarBox

The Beast

microADSB

For those that don't include software there are free options such as adsbScope and Virtual Radar Server.  Or for a one-off fee of Euros 25 plus VAT, you can use PlanePlotter.   

Or, you could start off with a DVB-T USB stick for around Euros 20 which will also work with adsbScope, VRS and PlanePlotter.  See:

http://www.flightradar24.com/dvbt-stick

The free websites rely on data feeds from those with Mode-S receivers and DVB-T sticks and coverage can only expand as the feeder population grows.

Finally, the available receivers and software have strengths and weaknesses and customer support varies.  So read through the forums before you choose.

There's also a free Guide to Radarspotting which you may find useful:

http://radarspotting.com/forum/index.php?action=tpmod;dl=item92

Thank you so much for your help.
I can do something with all these information
Thank you!