You have to know what a Lot in that area is selling for and add on the cost of NEW Construction in that square footage to really know anything.

When you see something bigger, or smaller you just know you need to adjust for those factors… more bedrooms, more square footage will rent for a little more.  

Maybe they added the extra square footage without permits? 

GO TO REDFIN,  SEARCH YOUR FAVORITE ZIP CODELOOK UP WHATEVER PROPERTY TYPE YOU WANT AND GO TO "SOLD" PROPERTIES WITHIN THE PAST 3 MONTHS ONLY OR EARLIER GO DOWN THE PAGE AND CLICK "DOWNLOAD ALL"IT WILL THEN PROMPT YOU TO OPEN AN EXCEL DOC- OPEN IT-FROM THERE FILTER THE PROPERTY PRICE LARGEST TO SMALLESTFIND THE AVERAGE PRICE BY HIGHLIGHTING THE ENTIRE "LIST PRICE" COLUMN OF THE SOLD PROPERTY SPREADSHEETAFTER CLICKING THE "AVERAGE" FUNCTION, YOU WILL BE GIVEN A DOLLAR AMOUNT- (BOLD THAT FIGURE) THEN GO TO THE SQUARE FEET COLUMN  AND DO THE SAME- FIND THE AVERAGE SQUARE FOOTAGE - THEN CLICK "AVERAGE" HIGHLIGHT THAT FIGURE TOODIVIDE THE AVERAGE DOLLAR AMOUNT OF ALL THE PROPERTIES SOLD WITHIN MAX 3 MONTHS FROM THE AVERAGE FIGURED SQUARE FOOTAGE TO GET YOUR MEDIAN PRICE PER SQUARE FOOTYOU WILL USE THIS FIGURE TO DETERMINE IF A PROPERTY WITHIN YOUR PREFERRED AREA CODE IS DEEPLY DISCOUNTEDTHEN, YOU WILL GO BACK TO REDFIN AND CHANGE THE SOLD TO ACTIVE AND DO ALL THE FILTERS PER YOUR PREFERENCE- "PUT IN KEYWORD AREA- "TLC" "CASH PURCHASE" , "NO FHA" AND "UNINSURED" AS WELL AS HAD A PRICE REDUCTION - EITHER MUTLTIPLE OR AT SOME POINT WHILE IT WAS LISTED HAS A REDUCTION (THIS USUALLY MEANS SELLER HAD HIS LISTING AGENT REDUCE PRICE BECAUSE HE WANTS TO SELL QUICKLY- ) SO IF A PROPERTY YOU FIND (AND THERE ARE A LOT) HAVE HAD 3 REDUCTIONS IN PRICE AND HAS BEEN LISTED FOR AWHILE...

Charge rent based on market rates and allocate based on square footage or amenities.

A couple doors down is a 4/1 fixer upper of the same square footage as the newly renovated unit and it's listed for $145k.

Appraisers simply take the square footage approach and don't seem to care about the extra kitchen and other amenities.

I am thinking about adding on to it to increase the square footage but am unsure about adding on to a manufactured home. 

Minimum bedroom square footage requirements come into play (a quick google search shows Texas having an 80sqft minimum size requirements for a single occupancy bedroom).  

I'll admit, I never bothered to properly measure the space, so the lease very clearly said "approximately" for square footage.