Keeps saying Memory card error

The SD controller in these doesn't support XC; no bueno. This is a common problem on many pre-2011 Canon cameras as a whole, so this isn't unique to yours. However, it's even worse on pre-2007 cameras; most don't even support SDHC! Yours is in the middle where XC is not supported, but it supports HC cards. This is why I tell people looking at used ones to avoid anything pre-2011/vetted to not be plagued by this problem. Essentially on the P&S side, 2007+ is safe for SDHC, but 2011+ is XC safe. DSLRs are a bit better. with the T2/T2i lack XC support problem, but the T3/T3i added XC support (and as such, for used cameras, I recommend the T3i/T3 minimum to compensate for this shortcoming; if not for the fact the T1i's are old enough to all have high shutter counts and more likely to ERR 20 due to a shutter failure).
For P&S cameras, the market hit them hard due to amount of troubled ones. Anything made from 2005 or older with CF support is a dead end (no HC support), 2006-present supports HC (no XC), 2011-present generally supports XC. These early cameras require a NOS NON-HC card, which is super expensive today when they come up due to their scarcity. HC models are spared from this issue, until we stop having easy access to 16GB or less cards as some of them do not take 32GB cards due to firmware or SD reader issues. You can't buy a new 16GB card easily; I have gotten them when clearanced out to get rid of them, but that's it now.
For the DSLRs, far better situation; T1i supports SD/SDHC (no XC), T2i supports SDXC, T3/T3i and up support SDXC; no issues with the T3 series and up.

This broken situation is why I dread the new generation wanting to buy these for "retro photos"; you think they will know about this problem? NOPE!!!
If you are seeking one out for this and see this post, check for SDHC support; the year is reliable, but you need to spot-check on some dubious cameras. AT LEAST CHECK FOR SDHC SUPPORT unless you want to pay $50 for a NOS 2GB SD card!

While it will not support SDXC, SDHC cards will work :-). This is good because you cannot buy non-HC cards now (even at 8GB) outside secondary markets like eBay sellers with old cards. If you find one it's well-used (and risky), or NOS ($$); market scarcity dictates these prices :/. Essentially, the open market wiped them out and jacked the prices on NOS legacy cards up. SDHC only goes up to 32GB, unlike XC which starts at 64GB and maxes at 2TB.

Get a 16GB SDHC and you'll be in good shape on this one, 32GB if you can find it. It's an issue with multiple factors, based on the camera: The cards require exFAT*, which creates this issue.
There are two groups of "bad cameras:

• 2009 and older: Hardware level controller; hard limited to 32GB. NO WORKAROUNDS. SDXC will never work.
• Late 2010 cameras: MAY be correctable with 3rd party firmware like Magic Lantern, but only if supported.

*Maybe if you can force it to format as FAT32? I dunno, I never tried it but I would trust it's ability to not corrupt like a fart. You can't reformat on camera if it fails, so you're not shooting for the day IF it fails.
I'm half tempted to test this with a known incompatible camera like the SD1200, but it has to be from 2010 max; 2011 was when they addressed the XC problem.