There are various synonyms for 'increase in affluence' that can be used depending on the context. One alternative is 'prosperity boost', which highlights an improvement in financial wealth. Another term that can be used is 'rise in wealth', which indicates an increase in the amount of money or assets owned by an individual, group, or country. 'Economic growth' is also a suitable synonym that emphasizes the growth of a nation's economy as a whole. 'Improvement in living standards' is another phrase that is often used to describe an increase in quality of life due to a boost in financial security. Ultimately, the precise synonym used will depend on the level of specificity required in the usage context.