People often confuse Apple's warranty with its iPhone repair service.
The warranty is really only meant to safeguard customers against products that are defective out of the box. Even if some get away with it, Apple really isn't supposed to fix your phone if you dropped it, spilled water on it, bricked it or if you're at fault in any other way.
If your phone is no longer covered by the warranty due to any circumstance, then you're looking at spending on Apple's Out-of Warranty Service. Not including shipping costs, Apple deducts $199 from your credit limit before even looking at your phone, whether it's for an iPhone 4 repair or an iPhone 3G repair. That's as much as a new phone with AT&T or Verizon!
The final fee will be determined afterwards, and this will leave you phoneless for a week.
So now you're looking at two options: getting a new phone or sending it to a third-party iPhone repair service. Sure, you can get a brand-new iPhone 3GS from AT&T for as low as $49 when you buy online. But that ties you up for the next two years. Not to mention that it requires a minimum data service starting at $15 per month. You can terminate your contract early, but at a high price. Outside of a contract, expect to fork out $300 to $400, and as much as $449 to $ 749 if you're neither a qualified customer nor eligible for an early upgrade.
Now, a professional iPhone 3G or iPhone 4 repair service, on the other hand, is undoubtedly the more affordable option. Depending on the type of damage, these services will only charge roughly $45 to a little over $100 for fixing an iPhone 4 or iPhone 3G. Repair services done by a professional can also help you avoid any mishaps you might run into if you do a D.I.Y. repair without enough electronics experience.
Even if you decide to get a new phone, it still pays to send your current one to an iPhone Repair Singapore service. You can then make some extra cash by selling it at a reasonable price.
If you're looking for the most efficient option to get your smartphone fixed, the best idea is to have the iPhone 3G or iPhone 4 repair done by an expert and avoid the hassle. At least a technician from a respected electronics repair company would be held responsible for any further damage. You'll also get a warranty on the repair. If they can't fix it, then they won't charge you a penny.