Question DDR4 rams speeds with R5 2400g

[uncommonusername]

I am planning on building a small itx build with a ryzen 5 2400g apu and I'm not sure what kind of ram I should get for it, particularly what ram speed. The mobo I got my eyes on specifies it's memory standard as: DDR4 3200(O.C.)/ 2933/ 2667/ 2400/ 2133. I know that the bigger the number is an indicator of better speed, but what I don't fully understand is if I would be able to install ram with a different speed (such as DDR4 3000) and also I'm confused about some of the pricing. From what I have seen, ram 2933 costs more than ram with 3000, but why is that? Shouldn't the 3000 modules cost more because they are faster? Because if I can I would rather get ram with ddr4 3000 over the 2933 to save money, granted that it'll work with the mobo. Also the reason I'm trying to avoid the 2667/2400/2133 is because from my understanding faster ram is best when going with a standalone apu, unless if I'm wrong?

 

[WildCard999]

Memory pricing isn't just about the speed but also timing/CL (lower is faster) which is why you may see a similar spec'd kit but much more expensive. For AMD Ryzen memory speed makes a bit difference in gaming performance as can be nearly a 20 FPS difference from 2133 to 3200mhz. For the 2400G I would recommend a good 2x8gb kit such as this...
PCPartPicker part list / Price breakdown by merchant

Memory: G.Skill - Ripjaws V Series 16 GB (2 x 8 GB) DDR4-3200 Memory ($99.99 @ Newegg)
Total: $99.99
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2019-03-28 08:42 EDT-0400

The speed/timings are good for Ryzen and will perform well. Depending on the motherboard you get you'll need to make sure the memory is in the right slots (A2/B2 or A1/B1) and that AXMP/DOCP (or whatever it's called based on manufacturer) is enabled in the BIOS for the memory to run at the correct speed. If 3000mhz memory is significantly cheaper where you are then that would be fine to use.