We still use the Leaded solder. It is easier for beginners to use. It has a better temperature range and supports more reheating cycles. The kits them self are ROHS complaint.
We like to buy:
- 500g spool
- 0.8mm dia
- flux core
- 63/37 or 60/40 (% tin / %lead)
We run the irons between 350C to 400C for this solder.
We see it selling on amazon for around $20. We have been buying on ALiExpress for $20 and waiting 30-60 days.