Pick the right Canon lane
Canon compact cameras are popular because many use familiar menus, common SD-style cards, and well-documented batteries. That does not mean every PowerShot is equally useful. Some are tiny fashion compacts. Some are AA-powered beginner bodies. Some are larger premium compacts. Start by choosing the lane, then compare the real setup cost.
For a strict older CCD look, focus on mid-2000s ELPH, A-series, G-series, and S-series bodies. For easier modern storage and cleaner files, later ELPH HS models can still be useful, but they will not feel exactly like a 2007 CCD compact.
Tiny pocket Canons
The Canon PowerShot SD1000 DIGITAL ELPH is the obvious starter: 2007, 7.1 MP effective, 1/2.5 inch type CCD, SDHC / SD / MMC storage, and NB-4L battery. The Canon PowerShot SD780 IS DIGITAL ELPH is a 2009 slim model with 12.1 MP effective resolution, a 1/2.3-inch type CCD, SDHC / SD / MMC cards, and NB-4L battery. Both suit pocket carry better than serious manual control.
If you want later convenience, the Canon PowerShot ELPH 100 HS is a 2011 model with 12.1 MP effective resolution, SD / SDHC / SDXC / MMC storage, and NB-4L battery. It is not the same CCD-era choice, but it can be easier to live with if you want a small Canon and common cards.
AA-powered safe choices
The Canon PowerShot A570 IS is a 2007 7.1 MP effective CCD camera with SD / SDHC / MultiMediaCard storage and 2x AA batteries. The Canon PowerShot A590 IS is a 2008 8.0 MP effective CCD camera with SD/SDHC support and 2x AA batteries. The Canon PowerShot A720 IS is a 2007 8.0 MP effective CCD camera with a 6x optical zoom, SDHC / SD / MMC cards, and 2 AA batteries.
These A-series cameras are not as tiny as the ELPH bodies, but they are friendly used buys. If the camera works, batteries are easy. For a beginner, that can matter more than a smaller body.
Premium compact routes
The Canon PowerShot G9 is a 2007 model with 12.1 MP effective resolution, a 1/1.7-inch type CCD, SDHC / SD / MMC cards, and NB-2LH battery. It is larger and more serious than a tiny ELPH. The Canon PowerShot S90 is a 2009 10 MP effective compact with a 1/1.7-inch type CCD, SDHC / SD / MMC cards, and NB-6L battery. The Canon PowerShot S95 is a 2010 10.0 MP effective model with SD / SDHC / SDXC support and NB-6L battery.
If you want more zoom, the Canon PowerShot SX200 IS is a 2009 12.1 MP effective CCD model with a 28-336mm equivalent lens, SDHC / SD / MMC storage, and NB-5L battery. It is not as pocket-sleek, but it gives more framing range.
How to choose
Buy the SD1000 or SD780 style if pocket size and flash snapshots are the priority. Buy the A570 IS, A590 IS, or A720 IS if you want AA batteries and less accessory risk. Buy the G9, S90, or S95 if you want a more serious compact. Before paying, use the used camera checklist, then verify the battery and memory card in the accessory guide.
Do not assume the most expensive PowerShot is the best one for you. A G-series body can be excellent, but it is larger and may be overkill for casual flash photos. A tiny ELPH is easier to bring, but gives less control. An A-series camera is less stylish, but AA batteries make it forgiving. Match the body to the way you will shoot, not just the model's reputation.
When comparing listings, give extra weight to included Canon batteries and chargers. Replacement batteries are available for many models, but an original-looking complete kit lowers uncertainty. Also check that the date/time battery warning, if shown, does not hide a larger power problem. Ask for one fresh test photo before paying.
Canon PowerShot G9: a larger 2007 PowerShot with a 1/1.7-inch type CCD and NB-2LH battery.
Next step: compare a pocket Canon like the SD1000, an AA Canon like the A590 IS, and a premium compact like the G9.