hmmm personaly I reckon if your doing it as a hobby, with no thought of making money off of it then your fine to use most brush packs, cut outs, etc.

Some comps have rules about what you use, but thats not an issue as long as you read the rules and follow them.

If your commercial then it makes sense to use brush packs and so forth, of course (as 43 stated) you have to check the usage terms associated with the brush packs. People dont realise that this applies to fonts as well. Almost every font I have looked at on dafont.com says that its okay for non-commercial use but permision must be obtained before being used for commercial use.

if your doing commercial work time is the issue, thats why font packs, brush packs, shapes, etc, sell for good money, time = money in the commercial world.