If you have any experience with coffee travel mugs you surly know how important it is to have a mug that won't spill or leak. Some of the cheap travel mugs are made of plastic and the seals tend to weaken over time. In bad cases these mugs will start leaking only when they are tipped over but even when you tip the mug up to take a drink from. Nobody wants a dribbling travel mug.
Good no spill coffee mugs are going to run over $10 a piece and the best no spill mugs will run over $20 but they are well worth the money they sell for. Larger 24 oz coffee mugs will also tend to be a bit higher in price. The reason for this is simple, the better a travel mug is at preventing spills, leaks, and dribbles the better it is at locking in air as well. This can help keep your coffee hot, your drinks cold, and your shirt dry from drips.
Coffee Travel Mug Lids
The lid of your travel mug is the most important part of a mug when it comes to whether it will spill or not. Many of the cheapest lids make no claims that their lid is designed to prevent spills. Cheap plastic travel mugs tend to have a sliding plastic piece which covers the drinking hole keeping the bulk of your beverage from splashing out but doing little to actually seal the top from a complete spill.
Better mugs which are usually a bit more expensive tend to have better lids which not only cover the drinking hole but also seal the hole from more significant spills. Usually the lids are screwed on with a better seal, often rubberized, and the drinking hole is sealed with a rubberized piece. This is much better but is very subjective to the quality of manufacturing.
As with anything you buy quality is sometimes worth the price you pay and sometimes it isn't. A travel mug for instance is fairly inexpensive and the change in price from the high end to the low end isn't that much. The best travel mug will run you around $25 whereas the cheapest mugs will run in the $5 range. If the increase in quality is worth it to you then by all means start shopping around for top of the line products.
If on the other hand you simply want a stainless steel coffee mug that will help minimize spills or a wide base ceramic mug for stability around the house then adjust your price range down. If you do look for a simple no spill coffee travel mug make sure to find one with a rubberized drinking hole stopper as this will be a much better investment for your money.