First off Nikolas, Welcome...
Before you go and get yourself all tangled up in a mess, there's a few things to learn first. Our state is heavy into
trunking so it's quite critical that you understand the basics. You see where the word 'trunking' is in blue? That's a link (in this case) to another section of this site, called a Wiki. There you will find many links where you can start to learn about this very important subject. Concentrate on the basics first, then move on to the Motorola sections. Take your time - this will take some getting used to.
Next, is the subject of handheld scanners. There are several that will do P25 decoding and other services as well. However, no one hears everything; part of the reason is that it's much too broad a subject. Concentrate first on one or two services, learn all you can about them and move on. While it's possible to get a handheld that has no locked out frequencies, such scanners have problems - for example, getting it serviced if something goes wrong.
The 'blocked' frequencies involve analog cellular phone, which, though still used in some areas, is quickly dying out due to other technologies (such as Nexhell...er...Nextel) simply pushing them out of the market. There are, in addition, formats and protocols that simply cannot be scanned, no matter which scanner you buy; you will learn about this more as time goes on.
Our list of
Digital Scanners includes the BCD396 and PRO96, probably the 2 kings of the hill (until the new PSR modelds come out this fall from GRE, anyway...) There has been very extensive discussions on how one performs over the other; use the search tools on the site to do your research. The article linked above will direct you to other sections of our Wiki with articles (wiki speak for 'web pages') on each scanner - along with reviews, software and much more.
There are numerous other topics you will need to learn, but these will do for a start.
73s Mike