For 300 zloties, it's better to do 10 pages at 30 zloties per page than 30 pages at 10 per.
So yes, if you hold out and keep quoting higher rates, you will obviously have fewer jobs. (Which is not necessarily true, but let's presume for the time being that it is.) However, that's not necessarily a bad thing.
- You'll be less tired and better rested. This will help your perception, avoid slips of attention and QA blunders, help you avoid uninspiring prose where it matters. Chances are you'll also catch more easily and think faster.
- You'll be happier with your work. This motivation will likely show in your work — and by all means do make sure it does! :)
- You'll have more time to accept last-minute jobs, emergencies (preferably for a solid urgency surcharge), jobs you like, pro bono (charity) jobs and such like.
- … Or for blogging, writing articles, attending conferences, watching webinars, reading books. In short, all sorts of CTD, service to the translation community, and even marketing and client acquisition. Overworked and underpaid translators don't have the time and strength to fight for a better fate.
- … Or for QA (Quality Assurance), which is one of the best — and easiest and cheapest — marketing tools and initiatives available to a translator. One just needs to stop regarding such QA as something along the lines of +10-25% unpaid time but rather see it as an investment in better testimonials, less client loss (and more client retention) and better jobs in the future. It's easier to satisfy and retain the clients you already have attracted than to attract new ones. As far as attracting new ones goes, however, the easiest way is word-of-mouth, i.e. referrals from your already existing (and hopefully talking) happy clients.
- Your health will last longer.
- Your relationships with family members and friends will be better for the added time you can spend cherishing them.
- It's easier to find more work than it is to raise your rates with existing clients at all or dramatically raise them with new clients (especially ones referred to you by your old clients, who probably mentioned the rates you were charging them). It's possible to progress gradually and get out of an undercharging situation, but it's hard to do.
Notwithstanding, I know a translator whose initial strategy was to be cheap — even dirt cheap — and book his calendar full as soon as possible. But he used the opportunity to gain good testimonials and his increasing experience — and accruing testimonials — to get better rates. His goal was not to be in a rut of low rates for a long time just to be neck-deep in jobs.
To some extent, thus, I suppose this is a subjective matter depending on what fits your personality best, and your goals.
Please consider, though, that if you wish to fill your calendar to the brim as a rookie — or even as a veteran in a pair and field where jobs are more scarce — there are other ways than lowering your prices for normal commercial clients. You can always donate your skills and time to those in the need, those who really need your translations, and the best you can do, but can't pay for them. Chances are the jobs will be more interesting than low-paying commercial jobs. The people you'll work with will likely also be more interesting, engaging and all-round nicer to work with. Even should you want to publicise your work for a marketing advantage, such as referrals, case studies, mentioning your clients on your website and so on — pro bono work has more potential for that sort of thing anyway.