Is there anything like the Sims 2 user startup cheat for Sims 3? Any way to use shortcuts for the cheats, such as "snapon / off" for the snapObjectsToGrid true or false cheat, for example?

There's a tool here to set cheat shortcuts: http://modthesims.info/d/391544 (I haven't tried it myself, but the comments suggest it's working).

Awesomemod has an option to have testingcheats enabled by default(set in the config file), so it is possible to have cheats that load on start-up via mods, but that's the only one I know of that does so. Nraas's Master Controller mod has a number of cheaty functions, but not game cheats as such.

Edit: There's some keyboard shortcuts that might be useful to you as well, actually: http://aniscreationssims.weebly.com...tcuts-list.html

I've used the Auto-Cheater for years and it works great if you take the time to set it to your preferences. Once in a while it will get corrupted if it's running during a hard shutdown of your computer, so make a duplicate copy.

Thank you both for responding! Still trying to figure my way around the game and I appreciate your help and the links.