Inventory slots are the single biggest cost in this game, followed by potatoes. Depending on how patient you are, the unvaulting system of Prime Resurgence has a rotation of about a year. Investing two potatoes in a frame and then their prime once they’re unvaulted is 40p, which is ultimately cheaper for most frames than the cost of a set + 20p for the potato. The only primes that are actually notable upgrades are Volt due to the extreme increase in energy pool, and to a much lesser extent Nidus and Valkyr due to better low level scaling from increased armour.
Inventory slots are the single biggest cost in this game, followed by potatoes. Depending on how patient you are, the unvaulting system of Prime Resurgence has a rotation of about a year. Investing two potatoes in a frame and then their prime once they’re unvaulted is 40p, which is ultimately cheaper for most frames than the cost of a set + 20p for the potato. The only primes that are actually notable upgrades are Volt due to the extreme increase in energy pool, and to a much lesser extent Nidus and Valkyr due to better low level scaling from increased armour.
In terms of which weapons to keep, hang on to anything with an Incarnon adaptor and anything part of a crafting tree, which you can check here: https://warframe.fandom.com/wiki/Weapons_Required_as_Crafting_Ingredients