1) you can wait for baby fairs to get the breast pump. That's one upcoming on Oct - "mummys market". You can join their facebook page for more information. And yes. you can purchase the accessories to replace for a secondhand pump. you can join "preloved baby goods" on facebook to keep a lookout for 2nd hand stuffs.
2) Pumps are very useful when babies are not good at latching and to build up supply. If your wife is very keen on breastfeeding long term, it is wise to invest in a good pump. Latching is a better way to stimulate the milk. If your baby can latch well, your wife can dl all the way and the pump can be used when your wife goes back to work or pump out excess milk. She can join "breastfeeding mums" on facebook to learn more about breastfeeding.