Take a look at the FLStat program which you might find helpful. It shows a lot of info from FL/Discovery such as ships, weapons amongst other things such as where items(ships, weapons etc) can be purchased.
This one seems to be the cheapest and it looks fairly reasonable if 4000 cargo is sufficient.
Base,Owner - Faction*,System,Price,Sells,Level Req'd,Rep. Req'd,Base Nickname,Equipment Nickname
Avon Hideout,The Maquis,Ile-de-France,50600120,yes,1,0.00,ga01_15_base,dsy_l_ane_package
Boulogne Base,Gallic Brigands,Picardy,50600120,yes,1,0.00,ga03_02_base,dsy_l_ane_package
Caussade Depot,The Maquis,Roussillon,50600120,yes,1,0.00,bw15_06_base,dsy_l_ane_package
Narbonne Base,Gallic Brigands,Languedoc,50600120,yes,1,0.00,ew13_04_base,dsy_l_ane_package
Ah I didn't notice that you wanted 5k or 4.7k min. Below is the list with a min 4.5k.
Code:
Ship,Class,Type,Price,Armor,Hold Size,Nanobots,Batteries,Max Angular Speed (deg/s),Angular Distance from 0 to 0.5 sec (deg),Time to 90% Max Angular Speed (s),Power Capacity,Power Recharge Rate,Thrust Capacity,Thrust Recharge Rate,Impulse Speed,Reverse Fraction,Nudge Force,Strafe Force,Nickname,Name ID,Info ID
Zoner Transport,9,freighter,130600120,53000,5000,350,350,13.37,4.64,0.3684,35000,4800,1000,100,90.00,0.55,30000.00,20000.00,dsy_z_whale,504132,504137
Bretonia Train,9,freighter,150600128,130000,5000,350,350,11.46,4.07,0.3454,60000,5000,1000,100,90.00,0.50,30000.00,16000.00,dsy_bretsupertransport,504403,504404
Liberty Supertransport,9,freighter,150600128,120000,5000,385,385,11.46,3.52,0.4912,30000,3000,1000,100,90.00,0.55,30000.00,20000.00,dsy_libsupertransport,504375,504376
Rheinland Train,9,freighter,160600128,130000,5000,350,350,11.08,3.40,0.4912,60000,5000,1000,100,90.00,0.55,30000.00,20000.00,dsy_rheinlandtrain,504411,504412
Gallic Advanced Train,9,freighter,190600128,88000,5000,315,315,10.31,3.36,0.4298,60000,5000,1000,100,90.00,0.55,30000.00,20000.00,dsy_gallic_train_adv,517059,517060
Kusari Train,9,freighter,170600128,100000,5000,350,350,10.03,3.56,0.3454,60000,5000,1000,100,90.00,0.55,30000.00,16000.00,dsy_kusaristransport,504399,504400
Heavy Tanker,9,freighter,185600112,104000,5000,400,400,9.55,3.26,0.3838,60000,5000,1000,100,90.00,0.55,30000.00,20000.00,dsy_hvytanker,501712,501713
Advanced Train,9,freighter,135600112,85000,5000,200,200,8.59,3.05,0.3454,60000,5000,1000,100,90.00,0.55,30000.00,16000.00,dsy_advanced_train,501660,501661
Kusari Tanker,6,freighter,80600120,60000,4700,360,360,13.37,4.64,0.3684,25000,3000,1000,100,90.00,0.55,30000.00,20000.00,dsy_gallofree,500826,500827
ALG Transport,9,freighter,125600120,112000,4700,480,480,11.46,3.63,0.4605,60000,5000,1000,100,90.00,0.55,30000.00,23000.00,dsy_algmover,503739,503740
Ageira Heavy Transport,8,freighter,108600120,166250,4500,500,500,11.46,4.97,0.1535,90000,7500,1000,100,90.00,0.55,30000.00,20000.00,dsy_ageira_b_transport,517256,517257