The Toffees have habitually sold in order to buy, but Moyes stressed that would not be the case in January, despite speculation suggesting he was willing to offload defender John Heitinga in order to raise money to buy Paris St Germain striker Kevin Gameiro, Toulouse youngster Wissam Ben Yedder and bring back Manchester City defender Joleon Lescott on loan.
"I'd like to (strengthen), but we know I've got a very small amount I could do anything with and I don't think it will probably be enough to make a difference in what we would want to bring in," he said."
Losing forward Kevin Mirallas and defender Tony Hibbert to injury for "a few weeks", and the club's current hold on fourth place, has not changed the Scot's view about the forthcoming window.
"We will probably look and see if there is anything out there but I don't think the situation with Mirallas and Hibbo would change that," he added.
"We wouldn't be letting anyone go, but we would like to add to it if we can, but we can only do that if the players were available and it was the right deal for us."
Everton will bid to maintain their fourth place at Stoke on Saturday, where goalkeeper Tim Howard is expected to make his 200th consecutive Barclays Premier League appearance.
The United States international has been an ever-present for more than five years, with the last time Everton played a league match without him coming on 23 September 2007 when Stefan Wessels deputised against Aston Villa.
"He has been a great buy for us. When I was losing Nigel Martyn I was saying 'Where am I going to get anyone as reliable, consistent with the same personality?'" added Moyes. "I've been very fortunate I've picked one that is good in all ways. He has been a great goalkeeper, he is great to have around and is a great ambassador for Everton.
"He is fit, he is good, his work-rate is excellent and we are really pleased to have him. When you leave Manchester United to come here, a lot can depend on how you react and he tried to rebuild himself and show how good a goalkeeper he was and I think he has proved that."