I am a Realtor and have a seller that has an assumable loan, but that still leaves $300K between the balance and the sales price.

@Jay HinrichsTo update this thread investigation was concluded and it was closed.

Hello everyone, As the title says, we are 3 weeks away from closing and we are in a big dilemma.

You might find that "saving" on taxes is small compared to what the property might be worth (talk with a trusted real estate agent who knows the area and can give a projection of property values).Don't forget to factor in closing costs (real estate fees, pro-rated property taxes, etc) and take into consideration your other income and/or investments. 

If you cash out refinance you incur (more or less) all the lending fees associated with a financed property purchase (even though you are just refinancing the property you already own), and then you incur significant fees when you sell the property (closing costs, commissions, etc).  

I put some numbers below into this Rent or Sell calculator.https://www.narpm.org/members/resources/rent-vs-sell-calculator/ESTIMATES ON ROI (15 year time frame)at 5% Appreciation would profit $100K if SELL nowat 6% Appreciation would have $3,500K more if KEEP and sell after 15 yearsat 7% Appreciation would profit 122K if KEEP and sell after 15 years(Assuming a conservative 6% ROI on money invested from sale.)NOTE: The property appreciated 10% in the last year so I’m thinking 7% over the next 10-15 is reasonable.DETAILSSale Value: $520,000 (Best guess)Paid: $437,000Original Mortgage: $415,000Mortgage Balance: $380,000Interest: 3.375%Monthly mortgage: $2,899Mortgage Difference: $1064Annual Taxes, Insurance, HOA etc**: $20,345**$13,865 (Non Homestead tax) $4,680 (HOA) $1,800 (Landlord Insurance)Monthly Rental Charge $3,500*Appreciation 7%Years to Hold: 15More assumptions used in ROI Estimates Above90% occupancy,15% capital gains charge6% selling feeRate of return on gains if selling now instead 6%Annual maintenance 1%Annual rent increase 4%$3,500 is slightly aggressive. unlikely I could get more.Thanks in advance for any constructive thoughts and comments!!!!

An appraiser will use comps that are close to your location and in similar size and condition.

I live really close to it and I was thinking it would be a good choice for me to start there as it´s cheaper than Barcelona and it also has an ok University.

the price is what someone would pay if i listed one for sale... which i haven't done and don't intend to do.since 2016, the rents in my little portfolio have never gone down. 

You can, however, ask a Realtor to just list your property in the MLS for a flat fee and do nothing else, meaning you answer any and all enquiries, show the property, do your own negotiations and make arrangements for the closing with either a title company or a real estate lawyer.