The problem is simply that there's not enough money.
Tips
grammar
就是 has multiple uses: (1) emphasis — 他就是老板 (He IS the boss); (2) concession — 就是...也... (even if...still...); (3) 'the thing is' — 就是有点贵 (it's just a bit expensive).
usage
In casual speech, 就是 is a common filler, like 'well' or 'you know': 就是嘛! (Exactly! / That's what I'm saying!)
