On deposit, don’t use a prepay currency card. The amount is reserved against the card and will reduce the balance until it’s cleared off which could be a month later. Same goes for using those types of cards in petrol stations.
Generally everything they try to sell you at the desk is a rip off. Plenty of third party insurances as there’s a big market in this now. Check they do cover the car properly though.
If you refuse the hire company insurances, they may reserve a higher deposit also.
https://www.theguardian.com/money/2012/jun/15/holiday-car-hire-10-ways-avoid-being-ripped-off
Hire prices vary a lot. Aside from fluctuations in markets, exchange rates and economy, they deliberately vary them based on the day of the week and time of the year. https://media.thinknum.com/articles/rental-car-price-trends/