DIY is the best, might wanna consider it and lookup some youtube repair guides
Battery is easy to replace, home button tricky on first try subsequent repairs easy.
Home Button+ battery should cost under $10 or so, need the pentalobe screwdriver also
Sometimes for home button it isn't the button itself that's not working. It could be the charging port assembly that's not working. The charging port assembly is combined with the home button connector.
There's a good guide made by a guy with a British accent, disassembling the iPhone on a toyogo box type of cover