They're a newly promoted team and the Spanish league is different to others like the English in that regard so no big surprise that the first season doesn't have an astonishing budget to splurge on (although I'm sure that their budget is bigger than most relegation battle and even mid table teams).
As time goes on? I'm sure that as long as the team starts getting results (and good ol' Turki is still in there), money will be pumped into the team's budget on a regular basis.