How do I know an offer isn't a scam?

You should consult with a Realtor, or someone who can advise you on the merits of the offer. Someone who understands the purchase agreement or sales contract. The devil will be in the details of their offer. Price is always one component of an offer, and terms will tell the tale of whether or not this is a scam.

Also depends if it's upgraded. If it's a full upgrade then if you are being offered anything less then something along line of your community or area comps, then it is a scam. On the other hand If it does need work, $25K for example, in repairs, to bring it up to 100% upgraded, then they will automatically take the estimated repairs off of the top of the After Repair Value, ARV and offer you enough where they can earn a good profit from the repair and sale. I'm here in FLA. If you need assistance send me a message.

If You're questioning it, then it may just be a scam...Your best bet would be to hire an appraiser and get a professional and written opinion on the value of Your home. They're not usually that expensive and You may gain a lot of money instead of getting scammed.

In this market I would be shocked. I would interview 1 or 2 local agents to see if they can help. I can refer you if you want.

You can have a local agent do a Broker Price Opinion (BPO) for a fee, or you can ask for a no obligation CMA (Comparative Market Analysis). I know agents in Florida and can connect you to the correct Realtor Partner. Send me a message and I can connect you with someone in your area. Good luck!