You'd probably have to get one online. I got mine from NDS-Gear.com, but I think if you're US based then DSCardWorld.com is a bit better, they also ship from the US but they seem to be a dollar or two cheaper as well - I'd highly recommend their customer service, they helped me set mine up pretty good.
Typically R4i cards are only bought online - but I wouldn't buy an Ri gold card. It's a fake card (the original R4i is red in colour). Most flash cards are made in china, including the r4i gold card. you can buy the latest version - r4i gold 3ds card online. It usually cost 2 weeks to delivery to you. As before said, the r4i gold 3ds is not the best r4i card. Maybe, the r4i sdhc 3ds is better.
Yes. Reformat the micro SD card before installing the kernel for the R4i SDHC. R4i sdhc card from r4i-sdhc.com accept a MicroSD card to run games and medias on Nintendo console. The MicroSD card is used for saveing R4i SDHC kernel and games. Such as Kingston or Sandisk. If you buy a r4i sdhc card, you should also take a Micro SD card.
Download kernel from r4i card official web,Un-zip kernel,Copy all files into microSD card,insert microSD card into R4i card,insert R4i card in to DSi.
You can buy the r4i 3ds card in some online store. They will ship to all over the world in 2 weeks. You can easily pay by paypal or credit card. Actually, the r4i 3ds card is made in china, and online shopping is much cheaper.
You don't need to reformat the r4i gold card. You just need to format the MicroSD card, and reinstall the r4i gold kernel and games. Nothing about the r4i gold card.
R4i SDHC card is very cheap in the market. expeciall in China. As this card is made in China, if your buy it on some Chinese onlie shop, such as r4town.com, the price is much cheaper. But if you buy the r4i sdhc card from European or United States, it may be much expensive.
you can't retail stores can't sell it.
R4 cards and similar flashcards are banned in the UK.
r4i 3ds card is inlegal in most country, including Pakistan. So it is hard to find loacal r4 shops in Pakistan. But you can buy r4i 3ds card in some online store they can ship to all over the world with Airmail or DHL. It is much confortable and fast.
there are many kinds of r4 cards in the market. the most popular flashcrd currently is the r4i gold 3ds card and the r4i sdhc 3ds card. in spite of the price, you can buy a supercard dstwo, it is powerfull. But if you consider the price, the r4i gold 3ds card will be most optional.
You can buy R4i cards online.
r4i gold and r4i sdhc card are most popular in players. both of them can support 3ds, dsi and ds lite. but personally, I think the r4i gold card has better compatibility.