Giving good value or results for the amount of money spent.
“Buying in bulk is more cost-effective, even though the upfront price looks higher.”
“This printer is the most cost-effective option since the ink cartridges last so long.”
This is a natural word for Task 5 whenever price and value are part of the comparison, and it sounds more precise than simply saying "cheap." Use it to argue that your choice offers the best balance between price and quality, which shows the examiner you're weighing more than just the sticker price.
Synonyms: economical, good value, budget-friendly