The U’s have seen their transfer budget increase this season, but Robinson says the additional funds are needed simply to keep up the pace in the market.
Rotherham dropped back down into the third tier following relegation from the Championship last term, but could face a competitive league.
Ipswich Town and Wigan Athletic have already flexed their financial muscles during the summer after takeovers, and may yet be joined by Sunderland and Portsmouth – who are both plotting major rebuilds ahead of the new campaign.
The likes of Sheffield Wednesday and Charlton Athletic are likely to be challenging at the top end of the division too, although the former are believed to be focusing on loan signings and free agents this summer.
But despite that, Robinson believes some of the spending in the third tier is now bordering on ‘ludicrous’.
Oxford have already spent money to secure the signing of Marcus McGuane from Nottingham Forest, but their manager admits they ‘can’t get anywhere near’ some of the figures being offered by other clubs this summer.
"We’re going to spend more money next season,” said Robinson, speaking to BBC Oxford.
“We have a transfer pot available which is brilliant, but we’re probably going to be in the same position in the (spending) league.
“We’re having to spend to stay anywhere near.
“There are teams in our league offering £10,000 a week for defenders and you’re thinking ‘this is ludicrous where this league is going’.
“We can’t get anywhere near this.”