I've used a Trespass rucksack for a few budget trips, and they generally offer decent quality for the price. Their bags tend to be durable enough for moderate use, but for extensive backpacking, you might notice wear and tear faster compared to higher-end brands.
Look for models with reinforced seams and sturdy zippers, as these areas often face the most stress. Some friends have recommended the Trespass Albus for day trips— it's affordable and has a good organizational design. However, for longer trips, you might want to check out their larger models like the Trek 85 if you need more space.
If you're doing extensive travel, it might be worth investing a bit more in a brand known for durability, like Osprey or Deuter. These brands often offer better support and comfort for longer treks. Ultimately, it depends on how intensively you'll be using it. Check reviews and if possible, try them in-store to ensure a good fit.