Interview Salary negotiation - Should I accept that 30% hike or wait for some time?

I am working (5years) in a small company and looking for a change now due to financial reasons, also my package is well below the market. The reason for such a stay was getting knowledge at the expense of money (though later I can cover up).
At the time of salary negotiation, when I ask for the salary as per market range, HR says they can give 30% only as per company standards. But at the time of screening, they says salary is not an issue. This has happened in few interviews(4/5). I have not accepted any of them.
Should I accept that 30% hike or wait for some time?
Also, I am trying to understand the reasons for the change in the statement?

Dear Param,

Still I do have the handicap of not working in any industrial organization both in the private and the public sector nor any first hand knowledge about salary fixation of recruits.

Yet based on my interactions with young job-seekers and experienced HR people, I am given to understand that in the case of hiring of already experienced candidates for the same or similar level jobs, the amount of salary lastly drawn in the previous organization which is comparatively small in size and scale of business turn over happens to be an important factor for initial salary fixation in the hiring organization.

In your perception, the offer of 30% hike may be less. But in stead of staying in the same organization dissatisfied, you switch for change with a hike of 30% only, in case where your career prospects are better in all other respects. Of course, ultimately, the decision is yours.