UPS Batteries
This isn't exactly a resource, but this worked for the Laser printer toner;
You can buy replacement batteries online:
https://smile.amazon.com/s/ref=nb_sb_noss_1/145-0164145-6127933?url=search-alias%3Daps&field-keywords=12v+ups+battery https://smile.amazon.com/s/ref=nb_sb_ss_i_1_22?url=search-alias%3Daps&field-keywords=back-ups+1300+battery https://smile.amazon.com/s/ref=nb_sb_noss_1?url=search-alias%3Daps&field-keywords=back-ups+es+750+battery https://smile.amazon.com/s/ref=nb_sb_ss_c_1_7?url=search-alias%3Daps&field-keywords=sla1075+battery http://www.refurbups.com/Replacement-Battery-Center-New http://www.batterymart.com/SEARCH.html?q=#/?_=1&filter.top_level_category=Sealed%20Lead%20Acid%20Batteries&filter.ssvoltage=12%20Volt&filter.volume.low=50.625&filter.volume.high=61.875 http://www.atbatt.com/ups-backup-batteries/apc/backups-es.asp http://www.batterysharks.com/Lead-Acid-Batteries-by-Volts-and-Amps-s/456.htm
If you're in a pinch and need a replacement fast, you can also get them local:
http://www.interstatebatteries.com/b/sealed-lead-acid-sla/11-0-13-0-volts/N-18Zzihwq2Zzihwsq?dsNav=A~Part+Number&1=1 Stores in Windsor Heights & Ankeny
https://www.batteriesplus.com/battery/ups/apc-(american-power-conversion)/backups-xs-series-bx1300lcd Stores in Urbandale & Ankeny