Where to purchase cables?

Power cords: whatever came with your system, because anything else won't matter one single bit. 

Speaker wire: any well made 12AWG OFC. Monoprice and Blue Jean Cables are cheap and effective. A coat hanger would literally sound just as good as any expensive snake oil brand but may be tougher to work with. :)

+1 for Morrow Audio

Schiit Audio sells good cables at very reasonable prices.

Generally speaking, one should purchase cabling at the same level as their audio chain. For instance, if one has a 100k system, high quality cabling is needed to prevent sonic bottlenecks. But if one has an entry system, then minimal should be spent on cabling.

@thermal

1. Are you asking where I personally purchase my cabling OR
2. Are you asking for low priced cabling OR
3. Are you asking for cabling that matches the level of your audio chain? We’d need to know the components in your chain to make relevant suggestions

Yes, sifting through cabling is very confusing beyond the marketing hype. 

I have experimented with lots of DIY and commercial cables without spending too much money. For commercial cables, I buy and sell almost exclusively on A’gon and USAudiomart. If you’re patient, you can buy, test and resell virtually any cable you want and break even. Good luck!