In general, I would expect to pay about $7 for a 16GB card, $12 for a 64GB card, and $17 for a 128GB card. The prices fluctuate all the time, so keep an eye out for deals.
In general, I recommend the cards listed below, in order of preference. I recommend you store that original card somewhere safe in case you run into any issues in the future, and buy new SD cards from a reputable brand like SanDisk or Samsung to use in your device. Your safest bet is to replace your cards with microSD cards from a well-known brand, which will prevent the cards from getting corrupted over time. In this guide I will show you how to set up each method. You can either use a single-card setup to host both your system files and the games on one card, or you can separate the two functions using a dual SD card setup.
The “TF2/EXT” slot is for your game files, so you will want a larger card for that one. The “TF1/INT” slot on your device holds the system firmware, so for that card 16GB is ideal. The RG35XX will come bundled with a single microSD card, and in some cases two SD cards, but they are from a generic brand and will be prone to failure. Sandisk (left) and Samsung (right) microSD cards
