Moyes is still to make his first significant signing since replacing Sir Alex Ferguson.
He had a joint bid for Everton duo Leighton Baines and Marouane Fellaini turned down on Monday and has also failed to prise Cesc Fabregas away from Barcelona.
However, whilst Moyes acknowledges his squad requires bolstering, he will not spend just for the sake of it.
"There is a need to do it but there's no pressure to do it," said Moyes.
"It's something we've been talking about it since I took the job on July 1.
"I have an idea of where I'd like to strengthen but we won't do it because people tell us we should be signing players.
"If the right players are available great, but if not the first thing we'll do is encourage our own young players in the squad to do as well as they did last year."
United have made it plain this summer they do have the funds to compete in the transfer market, a situation Moyes underlined.
"Yes I do (believe there is value in the market)," said Moyes.
"But we've only targeted certain players. We don't have a big, big list because there are only certain quality players we want to bring in to the club."
There is still the potential for exploring Juan Mata's availability at Chelsea, although any move for the midfielder would almost certainly be accompanied by Wayne Rooney's exit, something United have continued to insist will not happen.
"We have told you haven't we," said Moyes.
"I hardly need to repeat it again. It doesn't need to be said."
Moyes confirmed full-back Rafael would be missing for "three or four weeks" with a hamstring strain.
In addition, Nani (groin), Ashley Young (ankle) and Javier Hernandez (hamstring) will miss out on Monday night against Chelsea as they recover from their respective injuries.
"Really they are coming back from the effects of not having a proper pre-season because they came back from international duty a bit late," said Moyes.
"Hopefully they are all not too far away now."