Eddie Howe said Newcastle are "trying to get deals done" this summer but "to sign good players is very difficult".
The Magpies boss also said he doesn't want to lose any players currently in his squad but admitted that is out of his control.
Speaking to BBC Radio Newcastle after Saturday's pre-season win over Gateshead, Howe said: "I'm waiting for news on a daily basis to see what's happening.
"We want to bring the right players in to elevate our squad - but to sign good players is very difficult.
"We're in that process of talking, negotiating and trying to get deals done.
"'Financial fair play' are words I don't really like the sound of - but it's there in every conversation we have at the moment because it's relevant and impacting what we can and can't do.
"We have to be creative and sometimes think outside of the box with our transfers because we have a budget we have to stick to.
"I don't want to lose anyone from the squad we currently have; I want to build, and add quality players.
"But, of course, you're not always in control of that, so we'll wait and see if a player could leave - but certainly it wouldn't be something I want to happen."