Creating sound effects with virtual instruments (legality question)

Hello everyone! The Cakewalk community is super knowledgeable about all aspects of the music and audio business, so I wanted to ask for your expertise. 

I'm working on the soundtrack for a small Android game, and the developer may want me to create some sound effects as well. I have no experience with making SFX, but I imagine it may be kind of fun to try. However, I don't have any tools specifically for creating SFX. My question is whether useing virtual musical instruments to create SFX is allowed. For example, could I use a loud percussion sample as a gun shot? I feel like the licenses only allow for their samples to be used within the context of a musical composition. What if I altered the original sample using effects and/or combined it with other samples to make my own sound? 

Any help at all would be greatly appreciated. 

Thank you.

If you have free versions of synths or free downloads of samples you should check the license that came with them.  Free versions are often limited to "personal use only", though many are not.
 
Anything you've paid for it is a safe bet that you can do whatever you like. After all, the whole point of musical instruments (or any sound producing instrument) is to create noise that you then try to sell.   In the case of samples and sample libraries it's still best to check the license terms, there may or may not be royalties due and minor annoyances like that, but that would be up to the game publishers legal department to sort out.

Thanks for your input. I'll play around with what I have and see if I can make something usable. Whatever I do end up creating will definitely be altered from the original so I'm guessing I shouldn't run into any legal trouble. I doubt these companies have people listening that closely to SFX in games to see if someone is using their instruments (assuming they'd even have a problem if we did). 

There is a site called Freesound.org
Great place to get free sounds for use. Read the rules and the license that govern their use. Some allow total access. Others restrict their use with certain CC license.

I have some sounds I post there a few years ago. Have more that I need to post. Just keep forgetting. But it's a great resource.

Some sound libraries prohibt the use of recordings that expose the raw samples.. i.e. must be placed in a musical context..